1,847 research outputs found
A comparison of three Algorithms for Tracing Nonlinear Equilibrium Paths of Structural Systems
The relative efficiencies of the Riks/Wempner, Crisfield, and normal flow solution algorithms for tracking nonlinear equilibrium paths of structural systems are compared. It is argued that the normal flow algorithm maybe both more computationally efficient and more robust compared to the other two algorithms when tracing the path through severe nonlinearities such as those associated with structural collapse. This is demonstrated qualitatively by comparing the relative behaviors of each algorithm in the vicinity of a severe nonlinearity. Quantitative results are presented for the collapse a blade stiffened panel
Functional correlates of positional and gender-specific renal asymmetry in drosophila
Accordingly, the physical asymmetry of the tubules in the body cavity is directly adaptive. Now that the detailed machinery underlying internal asymmetry is starting to be delineated, our work invites the investigation, not just of tissues in isolation, but in the context of their unique physical locations and milieux
Increasing yield and profit by straight-cutting canola
Non-Peer ReviewedStraight combining canola (Brassica napus) can save producers time, fuel costs, and equipment wear. Research was undertaken at three locations to determine if straight combining shatter losses would be reduced sufficiently with higher yield potential to make straight combining viable in western Canada. This research employed a randomized complete block design. Treatments included crop density (low and high), fertility (low and high), time of weed removal (early and late), and harvest time (early and late). Factors were selected to offer a range of yields to evaluate the relationship between potential yield and shatter loss. Overall, factors causing shatter loss and crop yield differed between locations. Not surprisingly, crop density was affected by target crop density and percent green seed was affected by harvest timing
Increasing yield and profit by straight-cutting canola
Non-Peer ReviewedStraight combining canola (Brassica napus) can save producers time, fuel costs, and equipment wear. Research was undertaken at three locations to determine if straight combining shatter losses would be reduced sufficiently with higher yield potential to make straight combining viable in western Canada. This research employed a randomized complete block design. Treatments included crop density (low and high), fertility (low and high), time of weed removal (early and late), and harvest time (early and late). Factors were selected to offer a range of yields to evaluate the relationship between potential yield and shatter loss. Different components of potential yield were important in determining yield and seed losses before and during harvest operations. In Lacombe, fertility has been the most important factor. In Vegreville, timing of weed removal was paramount in 2006. At Scott in 2006, it appears that all operations must be conducted under best management practices or there is a substantially increased probability of reduced yield when straight-cutting. These results generally fit the hypothesis that ability to straight-cut is dependent upon maximizing potential yield. Under higher-yielding conditions, a key factor has led to success at straight-cutting. Under low-yielding conditions, all factors contributing to increased potential yield must be used to ensure feasibility of straight-cutting
Modelling the habitat of the endangered Carpentarian Grasswren (Amytornis dorotheae): The importance of spatio-temporal habitat availability in a fire prone landscape
Species distribution modelling (SDM), a tool increasingly adopted to quantify geographic range size, often predicts species’ distributions as static. However, habitat availability may exhibit spatial and temporal variation when dynamic processes, such as fire, determine suitability. Static SDM approaches may not satisfactorily represent this dynamic process. We investigated the potential use of SDM to quantify dynamic habitat availability by applying the MaxEnt SDM technique to model the habitat of the Carpentarian Grasswren (Amytornis dorotheae), an endangered Australian passerine dependent on long unburnt vegetation in a fire prone system. By adjusting a typical SDM approach to incorporate the dynamic nature of fire, we modelled the spatio-temporal variation of suitable habitat over 12 years and compared it to a static modelling approach. Incorporating fire as a dynamic process increased the importance of the fire variable to models (from 35% permutation importance) and improved model performance, as evaluated by the AUC using cross-validation. Our dynamic model revealed sizeable temporal variation in the area and spatial arrangement of suitable habitat that was not apparent in the static model. This result may partly solve the mystery of why the species occurs as widely separated populations despite the presence of seemingly suitable intervening habitat. In areas where the species is no longer found, habitat availability was less consistent due to frequent fire, and fire refugia was more limited and isolated, when compared to sites with recent records. These results demonstrate that, when compared to a static approach, a dynamic SDM approach can lead to improved understanding of dynamic ecological processes, and their impact on a species
Aging and Immortality in a Cell Proliferation Model
We investigate a model of cell division in which the length of telomeres
within the cell regulate their proliferative potential. At each cell division
the ends of linear chromosomes change and a cell becomes senescent when one or
more of its telomeres become shorter than a critical length. In addition to
this systematic shortening, exchange of telomere DNA between the two daughter
cells can occur at each cell division. We map this telomere dynamics onto a
biased branching diffusion process with an absorbing boundary condition
whenever any telomere reaches the critical length. As the relative effects of
telomere shortening and cell division are varied, there is a phase transition
between finite lifetime and infinite proliferation of the cell population.
Using simple first-passage ideas, we quantify the nature of this transition.Comment: 6 pages, 1 figure, 2-column revtex4 format; version 2: final
published form; contains various improvements in response to referee comment
Recommended from our members
Predicting population responses to environmental change from individual-level mechanisms: towards a standardized mechanistic approach
Animal populations will mediate the response of global biodiversity to environmental changes. Population models are thus important tools for both understanding and predicting animal responses to uncertain future conditions. Most approaches, however, are correlative and ignore the individual-level mechanisms that give rise to population dynamics. Here, we assess several existing population modelling approaches, and find limitations to both ‘correlative’ and ‘mechanistic’ models. We advocate the need for a standardised mechanistic approach for linking individual mechanisms (physiology, behaviour and evolution) to population dynamics in spatially explicit landscapes. Such an approach is potentially more flexible and informative than current population models. Key to realising this goal, however, is overcoming current data limitations, the development and testing of eco-evolutionary theory to represent interactions between individual mechanisms, and standardised multidimensional environmental change scenarios which incorporate multiple stressors. Such progress is essential in supporting environmental decisions in uncertain future conditions
Clarivate listed nursing journals in 2020: what they publish and how they measure use of social media
Objectives
To investigate what the most common types of articles that nursing journals purport to publish are and what they actually publish. And to investigate the extent to which academic nursing journals listed by Clarivate track alternative metrics.
Methods
Journals included in the nursing Journal Citation Report (JCR) journal category in 2019 described as nursing were identified and considered suitable for inclusion in the analysis. Instructions for authors were reviewed online and mention of each type of article is identified. The tables of contents of each issue of each journal published during 2019 were examined and the types of articles published were extracted to a spreadsheet into permitted article types and published articles. Likewise, the use of alternative metrics by each journal was extracted to a spreadsheet. Pearson's and Spearman's correlation analysis was applied to investigate the relationship between articles permitted and articles published.
Results
In the 2020 JCR, 123 journals were listed. The most common article type permitted was original research (n = 117), followed by review papers (n = 116), and discussion papers (n = 63). Original research (n = 7045); review papers (n = 1268); discussion papers (n = 1225); editorials (n = 793) and commentaries (n = 776) were the most commonly published categories of the article. Of journals examined, 108 (96.8%) tracked mentions on social media and the Altmetric score was most commonly used (75%). There was a strong correlation (r = 0.73; P = 0.002) between the numbers of articles permitted and published and a strong correlation (ρ = 0.86; P < 0.001) in terms of the rankings of the permitted and published articles.
Conclusions
There is a relationship between the most frequently permitted article types and those published, especially for the most frequent categories of both. Original articles, review papers, and discussion papers are the backbone of academic publishing in nursing with original articles vastly outweighing review and discussion papers. Most Clarivate listed journals now use some method of tracking alternative metrics indicating how seriously publishers take their social media profiles
A rapid allele-specific assay for HLA-A*32:01 to identify patients at risk for vancomycin-induced Drug Reaction with Eosinophilia and systemic symptoms
Human leukocyte antigen (HLA) alleles have been implicated as risk factors for immune-mediated adverse drug reactions. We recently reported a strong association between HLA-A*32:01 and vancomycin-induced drug reaction with eosinophilia and systemic symptoms (DRESS). Identification of individuals with the risk allele prior to or shortly after the initiation of vancomycin therapy is of great clinical importance to prevent morbidity and mortality, improve drug safety and antibiotic treatment options. A prerequisite to the success of a pharmacogenetic screening tests is the development of simple, robust, cost-effective single HLA allele test that can be implemented in routine diagnostic laboratories. In this study, we developed a simple, real-time allele-specific PCR for typing the HLA-A*32:01 allele. Four-hundred and fifty-eight DNA samples including thirty HLA-A*32:01-positive samples were typed by allele-specific PCR. Compared to ASHI accredited sequence-based high-resolution, full allelic HLA typing, this assay demonstrates 100% accuracy, sensitivity of 100% (95% CI: 88.43% to 100%) and specificity of 100% (95% CI: 99.14% to 100%). The lowest limit of detection of this assay using the Power Up SYBR Green is 10 ng of template DNA. The assay demonstrates a sensitivity and specificity to differentiate HLA-A*32:01 allele from closely related non-HLA-A*32 alleles and may be used in clinical settings to identify individuals with the risk allele prior or during the course of vancomycin therapy
Mapping the unique and shared functions of oncogenic KRAS and RIT1 with proteome and transcriptome profiling
Aberrant activation of RAS oncogenes is prevalent in lung adenocarcinoma, with somatic mutation of KRAS occurring in ∼30% of tumors. Recently, we identified somatic mutation of the RAS-family GTPase RIT1 in lung adenocarcinoma, but relatively little is known about the biological pathways regulated by RIT1 and how these relate to the oncogenic KRAS network. Here we present quantitative proteomic and transcriptomic profiles from KRAS-mutant and RIT1-mutant isogenic lung epithelial cells and globally characterize the signaling networks regulated by each oncogene. We find that both mutant KRAS and mutant RIT1 promote S6 kinase, AKT, and RAF/MEK signaling, and promote epithelial-to-mesenchymal transition and immune evasion via HLA protein loss. However, KRAS and RIT1 diverge in regulation of phosphorylation sites on EGFR, USO1, and AHNAK proteins. The majority of the proteome changes are related to altered transcriptional regulation, but a small subset of proteins are differentially regulated by both oncoproteins at the post-transcriptional level, including intermediate filament proteins, metallothioneins, and MHC Class I proteins. These data provide the first global, unbiased characterization of oncogenic RIT1 network and identify the shared and divergent functions of oncogenic RIT1 and KRAS GTPases in lung cancer
- …