358 research outputs found

    Regeneration Research

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    Imagine losing an eye, an arm or even your spinal cord. When we are wounded, our bodies, and those of other mammals, generally respond by sealing the wound with scar tissue. The newt, however, can repeatedly regenerate lost tissues, even as an adult. Recent research led by University of Dayton Biology Professor Panagiotis A. Tsonis and Chikafumi Chiba at the University of Tsukuba in Japan, published in the current volume of the prestigious journal Nature Communications, has shed some light on the newt’s exceptional regenerative ability and may provide further insight into regeneration in other species, including mammals

    Why Johnny Fails to Protect his Privacy

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    Albeit people worldwide cry out for the protection of their privacy, they often fail to successfully protect their private data. Possible reasons for this failure that have been identified in previous research include a lack of knowledge about possible privacy consequences, the negative outcome of a rational cost-benefit analysis, and insufficient ability for protection on the users’ side. However, these findings mainly base on theoretical considerations or results from quantitative studies, and no comprehensive explanation for users’ privacy behavior has been found so far. We thus conducted an interview study with 24 participants to qualitatively investigate what are (1) users’ mental models of privacy consequences, (2) obstacles for privacy protection, and (3) strategies for privacy protection. Our results provide evidence for all possible explanations: We find that most of our participants are indeed unaware of most consequences that could result from not protecting their privacy besides personalized advertisement and financial loss. We also identify several obstacles for privacy protection, such as protection being too much effort, too complicated, users lacking knowledge, or social aspects. Protection strategies mostly base on reducing the amount of data disclosed and most users refrain from using advanced PETs. We further identified additional factors which influence whether people adopt measures to protect their privacy and propose a model which subsumes all factors that are relevant for people’s decision to apply protection measures

    Influencing factors on agricultural transports and their effect on energy consumption and average speed

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    This article deals with the importance of transportation in agriculture, focusing on energy consumption and average speed of different agricultural transport vehicles. Transportation of goods is an important section of both logistics and agricultural production; therefore this article concentrates on the linkage of these two fields of study – agriculture and logistics. Against this background, current trends in logistics and their significance for and impact on agriculture are defined first. The presented data were collected via a road trial comparing agricultural transport vehicles to those commonly deployed in road haulage. The advantages of the well-established tractor lie – of course – in its high cross-country mobility and the many resulting fields of application on agricultural production. The off-road attributes of the tractor combined with the high level of soil protection are characteristics highly in its favor, especially when applying a single phase harvesting system. With multiphase transport chains on the other hand, the deployment of trucks can be the sensible choice because of their higher average speed and lesser fuel consumption compared to the tractor. Furthermore, the motorization of the tractor is a factor to be considered when choosing the right transport system, since a comparison between two forms of motorization showed clear differences in their road performance.   Keywords: agricultural transports, energy consumption, average transport speed, transport vehicle comparison

    Synthesis and characterization of the properties of thermosensitive elastomers with thermoplastic and magnetic particles for application in soft robotics

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    In the currently rapidly developing field of soft robots, smart materials with controllable properties play the central role. Thermosensitive elastomers are soft, smart materials whose material properties can be controlled by changing their temperature. The aim of this work is to investigate the mechanical properties, to analyze the surface, the inner structure, and the heat transfer within the thermosensitive elastomer materials. This should provide a knowledge base for new combinations, such as a combination of thermosensitive and the well-known magneto sensitive elastomers, in order to realize new applications. Thermoplastic polycaprolactone particles were incorporated into a flexible polydimethylsiloxane matrix to produce thermosensitive elastomer samples. With a low melting point in the range of 58-60°C, polycaprolactone offers good application potential compared to other thermoplastic materials such as polymethamethylacrylate with a melting point above 160°C. Test samples of different material compositions and geometries were made to examine temperature-depending material properties. Two useful effects were identified: temperature-dependent change in stiffness and the shape memory effect. In certain examinations, carbonyl iron particles were also included to find out if the two particle systems are compatible with each other and can be combined in the polydimethylsiloxane matrix without disadvantages. Changes in shore hardness before and after the influence of temperature were investigated. Micro computed tomography images and scanning electron microscopy images of the respective samples were also obtained in order to detect the temperature influence on the material internally as well as on the surface of the thermosensitive elastomers in combination with carbonyl iron particles. In order to investigate the heat transfer within the samples, heating tests were carried out and the influence of different particle concentrations of the thermosensitive elastomers with and without carbonyl iron particles was determined. Further work will focus on comprehensive investigations of thermo-magneto-sensitive elastomers, as this will enable the functional integration in the material to be implemented with increased efficiency. By means of the different investigations, the authors see future applications for this class of materials in adaptive sensor and gripper elements in soft robotics

    An example of fast old field succession in a traditionally managed rural landscape on the Slovenian Karst

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    We report an exceptionally fast grassland recovery process from a karst plateau in SW Slovenia. Vegetation of old fields with different ages was sampled using a chronosequence of fields abandoned 1, 3, 6, 9, 13, 15 and 100 years ago. We prepared dendrogram dividing the data set into 9 clusters that were further analyzed: diagnostic species, ecological conditions and life forms were evaluated. The initial stage of succession was characterized by segetal weeds and indicated high levels of soil nutrients. The second stage was dominated by dense patches of perennial forbs (most of them ruderal species) preferring also high levels of soil nutrients. The third stage was dominated by caespitose hemicryptophyte grasses, many of them of sub-Mediterranean origin. The first two stages took 13 years and both could be considered as early successional stages developing on nutrient rich soils. These stages were switched to late successional stage characterized by seminatural grassland species. The quick succession can probably be attributed to the rich species pool of natural grassland flora, the small size and annual mowing of abandoned agricultural fields and the close proximity of seed sources

    Fecal Glucocorticoid Measurements and Their Relation to Rearing, Behavior, and Environmental Factors in the Population of Pileated Gibbons ( Hylobates pileatus ) Held in European Zoos

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    Pileated gibbons (Hylobates pileatus) are rated as endangered according to the International Union of Conservation of Nature (IUCN) Red List. The captive population suffers from poor breeding success and is threatened to become overaged. Although several factors are likely to contribute to the poor breeding success, one in particular may be chronic stress associated with prolonged periods of high glucocorticoid (GC) output. We investigated fecal GC levels of pileated gibbons (Hylobates pileatus) and their relationship to specific life-history variables and environmental factors. After validation of an enzyme immunoassay for the measurement of 5-reduced 3α,11β-dihydroxy cortisol metabolites to assess GC output reliably in pileated gibbons, we collected fecal samples over several days from all 36 European adult pileated gibbons located in 11 institutions and compared GC levels to intrinsic individual parameters, husbandry, behavior, and breeding history. Age, sex, and origin (wild vs. captive born) had no effect on GC levels. However, unnaturally reared gibbons had higher GC levels and showed more behavioral abnormalities than parent-reared individuals. Further, nonreproducing gibbons living in a pair without infants had higher GC concentrations than gibbons living in a family, bachelor group, or as singletons. With respect to environmental factors, a large size of the inside enclosure and the existence of visual protection from visitors was associated with lower fecal GC output. The data indicate that rearing and housing conditions appear to correlate to GC levels in pileated gibbons housed under captive conditions. It is hoped this knowledge will support the future management of the species in captivity and thus lead to a more successful breeding of this endangered primat

    Mineralogical alterations in calcite powder flooded with MgCl2 to study Enhanced Oil Recovery (EOR) mechanisms at pore scale

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    Seawater injection into chalk-reservoirs on the Norwegian Continental Shelf has increased the oil recovery and reduced seabed subsidence, but not eliminated it. Therefore, understanding rock–fluid interactions is paramount to optimize water injection, predict and control water-induced compaction. Laboratory experiments on onshore and reservoir chalks have shown the need to simplify the aqueous chemistry of the brine, and also the importance of studying the effect of primary mineralogy of chalk to understand which ions interact with the minerals present. In this study, the mineralogy of the samples tested, are simplified. These experiments are carried out on pure calcite powder (99.95%), compressed to cylinders, flooded with MgCl2, at 130 °C and 0.5 MPa effective stress, for 27 and 289 days. The tested material was analysed by scanning and transmission electron microscopy, along with whole-rock geochemistry. The results show dissolution of calcite followed by precipitation of magnesite. The occurrence and shape of new-grown crystals depend on flooding time and distance from the flooding inlet of the cylinder. Crystals vary in shape and size, from a few nanometres up to 2 μm after 27 days, and to over 10 μm after 289 days of flooding and may crystallize as a single grain or in clusters. The population and distribution of new-grown minerals are found to be controlled by nucleation- and growth-rates along with advection of the injected fluid through the cores. Our findings are compared with in-house experiments on chalks, and allow for insight of where, when, and how crystals preferentially grow

    Maternal and fetal outcomes after uterine fundal pressure in spontaneous and assisted vaginal deliveries

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    AIM: This study aimed to evaluate maternal and fetal outcomes after uterine fundal pressure (UFP) in spontaneous and assisted vaginal deliveries. METHODS: In a retrospective cohort study, 9743 singleton term deliveries with cephalic presentation were analyzed from 2004 to 2013. Spontaneous and assisted vaginal deliveries were analyzed separately with and without the application of UFP. Odds ratios were adjusted in a multivariate logistic regression analysis. RESULTS: Prevalence of UFP was 8.9% in spontaneous and 12.1% in assisted vaginal deliveries. UFP was associated with a higher incidence of shoulder dystocia in both spontaneous (adjusted odds ratio [adj. OR] 2.44, confidence interval [CI] 95% 1.23-4.84) and assisted vaginal deliveries (adj. OR 6.88 CI 95% 3.50-13.53). Fetal acidosis (arterial umbilical pH<7.2) was seen more often after the application of UFP in spontaneous vaginal deliveries (adj. OR 3.18, CI 95% 2.64-3.82) and assisted vaginal deliveries (adj. OR 1.59 CI 95% 1.17-2.16). The incidence of 5'-Apgar<7 (adj. OR 2.19 CI 95% 1.04-4.6) and 10'-Apgar<7 (adj. OR 3.04 CI 95% 1.17-7.88) was also increased after the application of UFP in spontaneous deliveries. A higher incidence of anal sphincter tears (AST) (adj. OR 46.25 CI 95% 11.78-181.6) in the UFP group of spontaneous deliveries was observed. CONCLUSIONS: UFP is associated with increased occurrence of shoulder dystocia and fetal acidosis. In spontaneous deliveries, the risk for lower Apgar scores after 5 and 10 min is increased, as well as the risk for AST
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