2,137 research outputs found

    Using the soil and water assessment tool to simulate the pesticide dynamics in the data scarce Guayas River Basin, Ecuador

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    Agricultural intensification has stimulated the economy in the Guayas River basin in Ecuador, but also affected several ecosystems. The increased use of pesticides poses a serious threat to the freshwater ecosystem, which urgently calls for an improved knowledge about the impact of pesticide practices in this study area. Several studies have shown that models can be appropriate tools to simulate pesticide dynamics in order to obtain this knowledge. This study tested the suitability of the Soil and Water Assessment Tool (SWAT) to simulate the dynamics of two different pesticides in the data scarce Guayas River basin. First, we set up, calibrated and validated the model using the streamflow data. Subsequently, we set up the model for the simulation of the selected pesticides (i.e., pendimethalin and fenpropimorph). While the hydrology was represented soundly by the model considering the data scare conditions, the simulation of the pesticides should be taken with care due to uncertainties behind essential drivers, e.g., application rates. Among the insights obtained from the pesticide simulations are the identification of critical zones for prioritisation, the dominant areas of pesticide sources and the impact of the different land uses. SWAT has been evaluated to be a suitable tool to investigate the impact of pesticide use under data scarcity in the Guayas River basin. The strengths of SWAT are its semi-distributed structure, availability of extensive online documentation, internal pesticide databases and user support while the limitations are high data requirements, time-intensive model development and challenging streamflow calibration. The results can also be helpful to design future water quality monitoring strategies. However, for future studies, we highly recommend extended monitoring of pesticide concentrations and sediment loads. Moreover, to substantially improve the model performance, the availability of better input data is needed such as higher resolution soil maps, more accurate pesticide application rate and actual land management programs. Provided that key suggestions for further improvement are considered, the model is valuable for applications in river ecosystem management of the Guayas River basin

    Buyer animosity in business to business markets: evidence from the French nuclear tests

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    Abstract Academic studies of buyer reaction to unpopular political events in the country of origin of products have focused on consumer markets. This paper aims to extend Klein, Ettenson and Morris' [Klein, J., Ettenson, R., & Morris, M. (1998). The animosity model of foreign product purchase: An empirical test in the People's Republic of China. Journal of Marketing, 62(1), 89-101] concept of consumer animosity to industrial markets by comparing industrial and consumer buyer reaction to the nuclear tests conducted by France in the Pacific in the mid-1990s. It investigates whether firms in the B2B sector were affected more than those in B2C markets, whether entry mode was significant, and examines the way in which firms in the two market sectors responded. The results show that buyer animosity was less pronounced in industrial than in consumer markets. They also show that entry mode can influence the experience of animosity

    The golden death bacillus Chryseobacterium nematophagum is a novel matrix digesting pathogen of nematodes

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    Background: Nematodes represent important pathogens of humans and farmed animals and cause significant health and economic impacts. The control of nematodes is primarily carried out by applying a limited number of anthelmintic compounds, for which there is now widespread resistance being reported. There is a current unmet need to develop novel control measures including the identification and characterisation of natural pathogens of nematodes. Results: Nematode killing bacilli were isolated from a rotten fruit in association with wild free-living nematodes. These bacteria belong to the Chryseobacterium genus (golden bacteria) and represent a new species named Chryseobacterium nematophagum. These bacilli are oxidase-positive, flexirubin-pigmented, gram-negative rods that exhibit gelatinase activity. Caenorhabditis elegans are attracted to and eat these bacteria. Within 3 h of ingestion, however, the bacilli have degraded the anterior pharyngeal chitinous lining and entered the body cavity, ultimately killing the host. Within 24 h, the internal contents of the worms are digested followed by the final digestion of the remaining cuticle over a 2–3-day period. These bacteria will also infect and kill bacterivorous free-living (L1-L3) stages of all tested parasitic nematodes including the important veterinary Trichostrongylids such as Haemonchus contortus and Ostertagia ostertagi. The bacteria exhibit potent collagen-digesting properties, and genome sequencing has identified novel metalloprotease, collagenase and chitinase enzymes representing potential virulence factors. Conclusions: Chryseobacterium nematophagum is a newly discovered pathogen of nematodes that rapidly kills environmental stages of a wide range of key nematode parasites. These bacilli exhibit a unique invasion process, entering the body via the anterior pharynx through the specific degradation of extracellular matrices. This bacterial pathogen represents a prospective biological control agent for important nematode parasites

    The Extent of Engagement With Telehealth Approaches by Patients With Advanced Cancer: Systematic Review

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    BACKGROUND Telehealth approaches are increasingly being used to support patients with advanced diseases, including cancer. Evidence suggests that telehealth is acceptable to most patients; however, the extent of and factors influencing patient engagement remain unclear. OBJECTIVE The aim of this review is to characterize the extent of engagement with telehealth interventions in patients with advanced, incurable cancer reported in the international literature. METHODS This systematic review was registered with PROSPERO (International Prospective Register of Systematic Reviews) and is reported in line with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines. A comprehensive search of databases was undertaken for telehealth interventions (communication between a patient with advanced cancer and their health professional via telehealth technologies), including MEDLINE, Embase, CINAHL, PsycINFO, Cochrane Library, Sociological Abstracts, and Web of Science, from the inception of each electronic database up until December 31, 2020. A narrative synthesis was conducted to outline the design, population, and context of the studies. A conceptual framework of digital engagement comprising quantitative behavioral measures (frequency, amount, duration, and depth of use) framed the analysis of engagement with telehealth approaches. Frequency data were transformed to a percentage (actual patient engagement as a proportion of intended engagement), and the interventions were characterized by intensity (high, medium, and low intended engagement) and mode of delivery for standardized comparisons across studies. RESULTS Of the 19,676 identified papers, 40 (0.2%) papers covering 39 different studies were eligible for inclusion, dominated by US studies (22/39, 56%), with most being research studies (26/39, 67%). The most commonly reported measure of engagement was frequency (36/39, 92%), with substantial heterogeneity in the way in which it was measured. A standardized percentage of actual patient engagement was derived from 17 studies (17/39, 44%; n=1255), ranging from 51% to 100% with a weighted average of 75.4% (SD 15.8%). A directly proportional relationship was found between intervention intensity and actual patient engagement. Higher engagement occurred when a tablet, computer, or smartphone app was the mode of delivery. CONCLUSIONS Understanding engagement for people with advanced cancer can guide the development of telehealth approaches from their design to monitoring as part of routine care. With increasing telehealth use, the development of meaningful and context- and condition-appropriate measures of telehealth engagement is needed to address the current heterogeneity in reporting while improving the understanding of optimal implementation of telehealth for oncology and palliative care. TRIAL REGISTRATION PROSPERO (International Prospective Register of Systematic Reviews) CRD42018117232; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018117232

    Applicability of correlated digital image correlation and infrared thermography for measuring mesomechanical deformation in foams and auxetics

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    Cellular materials such as metal foams or auxetic metamaterials are interesting microheterogeneous materials used for lightweight construction and as energy absorbers. Their macroscopic behavior is related to their specific mesoscopic deformation by a strong structure-property-relationship. Digital image correlation and infrared thermography are two methods to visualize and study the local deformation behavior in materials. The present study deals with the full-field thermomechanical analysis of the mesomechanical deformation in Ni/PU hybrid foams and Ni/polymer hybrid auxetic structures performing a correlative digital image correlation and infrared thermography. Instead of comparing and correlating only the primary output variables of both methods, strain and temperature, also strain rates and temperature rates occurring during deformation were compared. These allow for a better correlation and more conclusive results than obtained using only the primary output variables

    Forested Riparian Zones Provide Important Habitat for Fish in Urban Streams

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    Riparian zones form a boundary between aquatic and terrestrial ecosystems, with disproportionate influences on food web dynamics and ecosystem functioning in both habitats. However, riparian boundaries are frequently degraded by human activities, including urbanization, leading to direct impacts on terrestrial communities and indirect changes that are mediated through altered connectivity with adjacent aquatic ecosystems. We investigated how riparian habitat influences fish communities in an urban context. We electrofished nine urban site pairs with and without forested riparian buffers, alongside an additional 12 sites that were located throughout the river networks in the Oslo Fjord basin, Norway. Brown trout (Salmo trutta) were the dominant fish species. Riparian buffers had weak positive effects on fish densities at low to moderate levels of catchment urbanization, whereas fish were absent from highly polluted streams. Subtle shifts in fish size distributions suggested that riparian buffers play an important role in metapopulation dynamics. Stable isotopes in fish from buffered reaches indicated dietary shifts, pointing to the potential for a greater reliance on terrestrial-sourced carbon. Combining these results, we postulate that spatially-mediated ontogenetic diet shifts may be important for the persistence of brown trout in urban streams. Our results show that using a food web perspective is essential in understanding how riparian buffers can offset impacts in urban catchments

    Differences in collagen prolyl 4-hydroxylase assembly between two Caenorhabditis nematode species despite high amino acid sequence identity of the enzyme subunits

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    The collagen prolyl 4-hydroxylases (P4Hs) are essential for proper extracellular matrix formation in multicellular organisms. The vertebrate enzymes are α2β2 tetramers, in which the β subunits are identical to protein disulfide isomerase (PDI). Unique P4H forms have been shown to assemble from the <i>Caenorhabditis</i> <i>elegans</i> catalytic α subunit isoforms PHY-1 and PHY-2 and the β subunit PDI-2. A mixed PHY-1/PHY-2/(PDI-2)<sub>2</sub> tetramer is the major form, while PHY-1/PDI- 2 and PHY-2/PDI-2 dimers are also assembled but less efficiently. Cloning and characterization of the orthologous subunits from the closely related nematode <i>Caenorhabditis</i> <i>briggsae</i> revealed distinct differences in the assembly of active P4H forms in spite of the extremely high amino acid sequence identity (92-97%) between the <i>C. briggsae</i> and <i>C. elegans</i> subunits. In addition to a PHY-1/PHY-2(PDI-2)<sub>2</sub> tetramer and a PHY-1/PDI-2 dimer, an active (PHY- 2)<sub>2</sub>(PDI-2)<sub>2</sub> tetramer was formed in <i>C. briggsae</i> instead of a PHY-2/PDI-2 dimer. Site-directed mutagenesis studies and generation of inter-species hybrid polypeptides showed that the N-terminal halves of the <i>Caenorhabditis</i> PHY-2 polypeptides determine their assembly properties. Genetic disruption of <i>C. briggsae phy-1</i> (<i>Cb-dpy-18</i>) via a <i>Mos1</i> insertion resulted a small (short) phenotype that is less severe than the dumpy (short and fat) phenotype of the corresponding <i>C. elegans</i> mutants (<i>Ce-dpy-18</i>). <i>C. briggsae</i> <i>phy-2</i> RNA interference produced no visible phenotype in the wild type nematodes but produced a severe dumpy phenotype and larval arrest in <i>phy-1</i> mutants. Genetic complementation of the <i>C. briggsae</i> and <i>C. elegans</i> <i>phy-1</i> mutants was achieved by injection of a wild type <i>phy-1</i> gene from either species

    Global patterns of freshwater species diversity, threat and cross-taxon congruence

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    Aim Global-scale studies are required to identify broad-scale patterns in the distributions of species, to evaluate the processes that determine diversity and to determine how similar or different these patterns and processes are among different groups of freshwater species. Broad-scale patterns of spatial variation in species distribution are central to many fundamental questions in macroecology and conservation biology. We aimed to evaluate how congruent three commonly used metrics of diversity were among taxa for six groups of freshwater species. Location Global. Methods We compiled geographical range data on 7083 freshwater species of mammals, amphibians, reptiles, fishes, crabs and crayfish to evaluate how species richness, richness of threatened species and endemism are distributed across freshwater ecosystems. We evaluated how congruent these measures of diversity were among taxa at a global level for a grid cell size of just under 1°. Results We showed that although the risk of extinction faced by freshwater decapods is quite similar to that of freshwater vertebrates, there is a distinct lack of spatial congruence in geographical range between different taxonomic groups at this spatial scale, and a lack of congruence among three commonly used metrics of biodiversity. The risk of extinction for freshwater species was consistently higher than for their terrestrial counterparts. Main conclusions We demonstrate that broad-scale patterns of species richness, threatened-species richness and endemism lack congruence among the six freshwater taxonomic groups examined. Invertebrate species are seldom taken into account in conservation planning. Our study suggests that both the metric of biodiversity and the identity of the taxa on which conservation decisions are based require careful consideration.As geographical range information becomes available for further sets of species, further testing will be warranted into the extent to which geographical variation in the richness of these six freshwater groups reflects broader patterns of biodiversity in fresh water
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