437 research outputs found
Quaternary Trialkyl(polyfluoroalkyl)ammonium Salts including Liquid Iodides
New quaternary ammonium salts that contain polyfluorinated alkyl substituents were prepared by the polyfluoroalkylation of tertiary amines with polyfluorinated alkyl iodides. Metathesis reactions of the iodide salts with fluorine-containing anions resulted in new low melting salts. The iodide salts of the tri(isooctyl)polyfluoroalkyl amines are also liquids at 25°C
Death feigning as an adaptive antiâpredator behaviour: Further evidence for its evolution from artificial selection and natural populations
Death feigning is considered to be an adaptive antipredator behaviour. Previous studies on Tribolium castaneum have shown that prey which death feign have a fitness advantage over those that do not when using a jumping spider as the predator. Whether these effects are repeatable across species or whether they can be seen in nature is, however, unknown. Therefore, the present study involved two experiments: (a) divergent artificial selection for the duration of death feigning using a related species T. freemani as prey and a predatory bug as predator, demonstrating that previous results are repeatable across both prey and predator species, and (b) comparison of the deathâfeigning duration of T. castaneum populations collected from field sites with and without predatory bugs. In the first experiment, T. freemani adults from established selection regimes with longer durations of death feigning had higher survival rates and longer latency to being preyed on when they were placed with predatory bugs than the adults from regimes selected for shorter durations of death feigning. As a result, the adaptive significance of deathâfeigning behaviour was demonstrated in another preyâpredator system. In the second experiment, wild T. castaneum beetles from populations with predators feigned death longer than wild beetles from predatorâfree populations. Combining the results from these two experiments with those from previous studies provided strong evidence that predators drive the evolution of longer death feigning
Making judgements about students making work : lecturersâ assessment practices in art and design.
This research study explores the assessment practices in two higher education art and design departments. The key aim of this research was to explore art and design studio assessment practices as lived by and experienced by art and design lecturers. This work draws on two bodies of pre existing research. Firstly this study adopted innovative methodological approaches that have been employed to good effect to explore assessment in text based subjects (think aloud) and moderation mark agreement (observation). Secondly the study builds on existing research into the assessment of creative practice. By applying thinking aloud methodologies into a creative practice assessment context the authors seek to illuminate the âin practiceâ rather than espoused assessment approaches adopted. The analysis suggests that lecturers in the study employed three macro conceptions of quality to support the judgement process. These were; the demonstration of significant learning over time, the demonstration of effective studentship and the presentation of meaningful art/design work
Control of Biohazards: A High Performance Energetic Polycyclized Iodine-Containing Biocide
The article of record as published may be found at http://dx.doi.org/10.1021/acs.inorgchem.8b01600Biohazards and chemical hazards as well as radioactive hazards have always been a threat to human health. The search for solutions to these problems is an ongoing worldwide effort. In order to control biohazards by chemical methods, a synthetically useful fused tricyclic iodine-rich compound, 2,6-diiodo-3,5-dinitro-4,9-dihydrodipyrazolo [1,5a:5',1'-d][1,3,5]triazine (5), with good detonation performance was synthesized, characterized, and its properties determined. This compound which acts as an agent defeat weapon has been shown to destroy certain microorganisms effectively by releasing iodine after undergoing decomposition or combustion. The small iodine residues remaining will not be deleterious to human life after 1 month.Financial support of the Office of Naval Research (N00014-16- 1-2089), and the Defense Threat Reduction Agency (HDTRA 1-15-1-0028) is gratefully acknowledged. The M. J. Murdock Charitable Trust (No. 2014120) is thanked for funds supporting the purchase of a 500 MHz NMR.Financial support of the Office of Naval Research (N00014-16- 1-2089), and the Defense Threat Reduction Agency (HDTRA 1-15-1-0028) is gratefully acknowledged. The M. J. Murdock Charitable Trust (No. 2014120) is thanked for funds supporting the purchase of a 500 MHz NMR
Energy and Biocides Storage Compounds: Synthesis and Characterization of Energetic Bridged Bis(triiodoazoles)
The article of record as published may be found at https://doi.org/10.1021/acs.inorgchem.7b02277Energetic bridged triiodopyrazoles and triiodoimidazoles were designed and synthsized by reacting potassium triiodopyrazolate or triiodoimidazolate with corresponding dichloro compounds. All compounds were fully characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and elemental analyses. The structure of compound 1 was further confirmed by single-crystal X-ray diffraction. All of the compounds exhibit good thermal stability with decomposition temperatures between 199 and 270 °C and high densities ranging from 2.804 to 3.358 g/cm3. The detonation performances and the detonation products were calculated by CHEETAH 7. Compound 3 (Dv = 4765 m sâ1; P = 17.9 GPa) and compound 7 (Dv = 4841 m sâ1; P = 18.5 GPa) show comparable detonation pressure to TNT, and high iodine content makes them promising as energy and biocides storage compounds.This work was supported by the Office of Naval Research (N00014-16-1-2089) and the Defense Threat Reduction Agency (HDTRA 1-15-1-0028). The authors thank the M. J. Murdock Charitable Trust, Vancouver, WA (Reference No.: 2014120: MNL:11/20/2014), for funds to purchase a 500 MHz NMR spectrometer.
Parent experiences with a nurse-supervised community health worker asthma home-visiting program.
OBJECTIVE: This study seeks to identify helpful components of a nurse-supervised Community Health Worker (CHW) asthma home-visiting program, obtain feedback from parents and families about their experiences, and receive suggestions for new services that the program could provide. METHODS: Likert scale ratings and semi-structured qualitative interviews were conducted with parents who were selected from a representative sample and previously participated in the program. Five-point Likert scale ratings from 1 (not helpful) to 5 (very helpful) were obtained for 11 program components. Interviews were analyzed using a grounded theory participatory approach. Data were analyzed and themes were identified by two different coders using Dedoose software. RESULTS: A total of 22 participants were enrolled and 20 participants completed Likert scale ratings and qualitative interviews. Likert scale ratings (mean standard deviation [SD]) show that program strengths include asthma education (4.75 [0.55]), supplies (4.65 [0.99]), help with housing conditions (3.94 [1.56], pest management (3.79 [1.69]) and greater access to community resources (3.70 [1.30]). The ratings suggest that families need more help with other social determinants of health, such as school, lack of enough money or food, and mental health and behavioral concerns (3.05 [1.78]). Interviews echoed these ratings and revealed several themes about family and parental stress, children's activity limitations, desire for outreach after the 12-month intervention, a need for help with other social determinants and more emotional support. CONCLUSIONS: This study shows that the program was well received and reveals the importance of addressing social determinants of health and behavioral health concerns
Marine plastics threaten giant Atlantic Marine Protected Areas.
There has been a recent shift in global perception of plastics in the environment, resulting in a call for greater action. Science and the popular media have highlighted plastic as an increasing stressor [1,2]. Efforts have been made to confer protected status to some remote locations, forming some of the world's largest Marine Protected Areas, including several UK overseas territories. We assessed plastic at these remote Atlantic Marine Protected Areas, surveying the shore, sea surface, water column and seabed, and found drastic changes from 2013-2018. Working from the RRS James Clark Ross at Ascension, St. Helena, Tristan da Cunha, Gough and the Falkland Islands (Figure 1A), we showed that marine debris on beaches has increased more than 10 fold in the past decade. Sea surface plastics have also increased, with in-water plastics occurring at densities of 0.1 items m-3; plastics on seabeds were observed at †0.01 items m-2. For the first time, beach densities of plastics at remote South Atlantic sites approached those at industrialised North Atlantic sites. This increase even occurs hundreds of meters down on seamounts. We also investigated plastic incidence in 2,243 animals (comprising 26 species) across remote South Atlantic oceanic food webs, ranging from plankton to seabirds. We found that plastics had been ingested by primary consumers (zooplankton) to top predators (seabirds) at high rates. These findings suggest that MPA status will not mitigate the threat of plastic proliferation to this rich, unique and threatened biodiversity
Historical and contemporary factors generate unique butterfly communities on islands
The mechanisms shaping island biotas are not yet well understood mostly because of a lack of studies comparing eco-evolutionary fingerprints over entire taxonomic groups. Here, we linked community structure (richness, frequency and nestedness) and genetic differentiation (based on mitochondrial DNA) in order to compare insular butterfly communities occurring over a key intercontinental area in the Mediterranean (Italy-Sicily-Maghreb). We found that community characteristics and genetic structure were influenced by a combination of contemporary and historical factors, and among the latter, connection during the Pleistocene had an important impact. We showed that species can be divided into two groups with radically different properties: widespread taxa had high dispersal capacity, a nested pattern of occurrence, and displayed little genetic structure, while rare species were mainly characterized by low dispersal, high turnover and genetically differentiated populations. These results offer an unprecedented view of the distinctive butterfly communities and of the main processes determining them on each studied island and highlight the importance of assessing the phylogeographic value of populations for conservation
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