554 research outputs found
Temptation of academic medicine: Second alma mater and "shared employment" concepts as possible way out?
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Fall applied ethephon and temperature effects on flower bud growth and ovule longevity in Prunus domestica
In the Pacific Northwest some prune cultivars often exhibit inconsistent fruit set. Several factors have been associated with this characteristic. Temperature, genotype and boron content are among the most frequently mentioned. Studies were conducted to determine the effect of fall ethephon application on flower bud growth and ovule longevity in two Prunus domestica L. cultivars, 'Italian' and 'Brooks'. Ethephon was applied at the 60% leaf drop stage in the years 1988 and 1989. Growth of terminal buds, as well as tissue mineral content was determined from 50 days prior to bloom until immediately prior to bloom. Ovule longevity was determined by UV fluorescence microscopy after staining ovules with aniline blue. Temperature effects on ovule longevity were determined in flowers of excised twigs held for 18 days after full bloom in growth chambers at 5, 10, 15 and 20°C. Ethephon application reduced the growth rate of buds for the cultivars by having an effect on both fresh and dry weight. Mineral content of buds was markedly affected in the case of 'Italian'. Higher concentration of Ca and lower concentration of P, as well as higher B content were present in the ethephon treated buds of this cultivar, when compared to the untreated control buds. No difference was seen for N or K. 'Brooks' seemed not to be affected by ethephon application in terms of the mineral content of its buds. Under field conditions 'Brooks' showed a higher ovule viability than 'Italian'. Eighty percent of the 'Brooks' flowers had at least one viable ovule at 20 days after full bloom (DAFB). On the same date, only 40% of the flowers of 'Italian' had viable ovules, and 60% showed total ovule senescence. Ethephon application altered these genotypic differences. Flowers of ethephon-treated 'Italian' trees started with less viable ovules at full bloom, but these remained viable for a longer time. At 20 DAFB, ethephon-treated trees, in 80% of the cases, had at least one viable ovule. Ethephon did not change the pattern of ovule longevity of 'Brooks'. Increasing temperatures significantly reduced the viability of the ovules across the days, in both cultivars. At 5°C, both cultivars showed a low rate of ovule senescence and differences between 'Brooks' and 'Italian' were explained by the initial lower viability of 'Italian' at bloom time. As temperature increased, ovule senescence was faster in 'Italian'. At 15°C, only one ovule per flower remained viable by 8 DAFB. At 20°C, total ovule senescence in some flowers had already occurred by 2 DAFB, four days earlier than in 'Brooks'. Ethephon application markedly affected the rate of ovule senescence, depending on the temperature treatment and the genotype. In 'Italian', a clear effect on delayed ovule senescence was seen at 15°C and 20°C. At both temperatures, total ovule senescence was delayed at least by four days. As the temperature decreased, there appeared to be little difference between the ethephon-treated flowers and their controls. For 'Brooks' only a slight effect on ovule longevity was observed at 20°C
Five-year publication rate of clinical presentations at the open and closed American shoulder and elbow surgeons annual meeting from 2005–2010
© 2016, The Author(s). Background: The purpose of this study was to evaluate the five-year publication rate of papers presented at both the open and closed American Shoulder and Elbow Surgeons’ (ASES) annual meetings from 2005 to 2010. Methods: Online abstracts of the presentations at the open and closed ASES annual meetings were independently screened for clinical studies and graded for quality using level of evidence. The databases PubMed (MEDLINE), Ovid (MEDLINE), and EMBASE were comprehensively searched for full-text publications corresponding to these presentations and any paper published within five years of the presentation date was counted. Results: Overall, 131/266 papers corresponding to the meeting presentations were identified for a five-year publication rate of 49.2 %. Sixty two (48 %) of the papers were published in The Journal of Shoulder and Elbow Surgeons, 23 (18 %) were published in The American Journal of Sports Medicine, and 20 (16 %) were published in The Journal of Bone and Joint Surgery. The mean patient sample size included in presentations with a subsequent full-text publication was higher (154; standard error =27) than the presentations not published (93; standard error = 13) (p = 0.039). There was no correlation (p = 0.248) between the publication rate and the level of evidence of the presentations. Conclusions: The publication rate of presentations at ASES meetings from 2005 to 2010 is similar to that reported from other orthopaedic meetings. Studies with large sample sizes should continue to be encouraged, and high quality presentations must consistently be followed up with full-text manuscript preparation in order to maximize the future clinical impact
An Efficient Block Circulant Preconditioner For Simulating Fracture Using Large Fuse Networks
{\it Critical slowing down} associated with the iterative solvers close to
the critical point often hinders large-scale numerical simulation of fracture
using discrete lattice networks. This paper presents a block circlant
preconditioner for iterative solvers for the simulation of progressive fracture
in disordered, quasi-brittle materials using large discrete lattice networks.
The average computational cost of the present alorithm per iteration is , where the stiffness matrix is partioned into
-by- blocks such that each block is an -by- matrix, and
represents the operational count associated with solving a block-diagonal
matrix with -by- dense matrix blocks. This algorithm using the block
circulant preconditioner is faster than the Fourier accelerated preconditioned
conjugate gradient (PCG) algorithm, and alleviates the {\it critical slowing
down} that is especially severe close to the critical point. Numerical results
using random resistor networks substantiate the efficiency of the present
algorithm.Comment: 16 pages including 2 figure
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Crashworthiness simulation of composite automotive structures
In 1990 the Automotive Composites Consortium (ACC) began the investigation of crash worthiness simulation methods for composite materials. A contract was given to Livermore Software Technology Corporation (LSTC) to implement a new damage model in LS-DYNA3DTM specifically for composite structures. This model is in LS-DYNA3DTM and is in use by the ACC partners. In 1994 USCAR, a partnership of American auto companies, entered into a partnership called SCAAP (Super Computing Automotive Applications Partnership) for the express purpose of working with the National Labs on computational oriented research. A CRADA (Cooperative Research and Development Agreement) was signed with Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, Sandia National Laboratory, Argonne National Laboratory, and Los Alamos National Laboratory to work in three distinctly different technical areas, one of which was composites material modeling for crash worthiness. Each Laboratory was assigned a specific modeling task. The ACC was responsible for the technical direction of the composites project and provided all test data for code verification. All new models were to be implemented in DYNA3D and periodically distributed to all partners for testing. Several new models have been developed and implemented. Excellent agreement has been shown between tube crush simulation and experiments
Liposome Co-sedimentation and Co-flotation Assays to Study Lipid-Protein Interactions
A large proportion of proteins are expected to interact with cellular membranes to carry out their physiological functions in processes such as membrane transport, morphogenesis, cytoskeletal organization, and signal transduction. The recruitment of proteins at the membrane-cytoplasm interface and their activities are precisely regulated by phosphoinositides, which are negatively charged phospholipids found on the cytoplasmic leaflet of cellular membranes and play critical roles in membrane homeostasis and cellular signaling. Thus, it is important to reveal which proteins interact with phosphoinositides and to elucidate the underlying mechanisms. Here, we present two standard in vitro methods, liposome co-sedimentation and co-flotation assays, to study lipid-protein interactions. Liposomes can mimic various biological membranes in these assays because their lipid compositions and concentrations can be varied. Thus, in addition to mechanisms of lipid-protein interactions, these methods provide information on the possible specificities of proteins toward certain lipids such as specific phosphoinositide species and can hence shed light on the roles of membrane interactions on the functions of membrane-associated proteins.Peer reviewe
Glaucoma diagnosis using multi-feature analysis and a deep learning technique
AbstractIn this study, we aimed to facilitate the current diagnostic assessment of glaucoma by analyzing multiple features and introducing a new cross-sectional optic nerve head (ONH) feature from optical coherence tomography (OCT) images. The data (n = 100 for both glaucoma and control) were collected based on structural, functional, demographic and risk factors. The features were statistically analyzed, and the most significant four features were used to train machine learning (ML) algorithms. Two ML algorithms: deep learning (DL) and logistic regression (LR) were compared in terms of the classification accuracy for automated glaucoma detection. The performance of the ML models was evaluated on unseen test data, n = 55. An image segmentation pilot study was then performed on cross-sectional OCT scans. The ONH cup area was extracted, analyzed, and a new DL model was trained for glaucoma prediction. The DL model was estimated using five-fold cross-validation and compared with two pre-trained models. The DL model trained from the optimal features achieved significantly higher diagnostic performance (area under the receiver operating characteristic curve (AUC) 0.98 and accuracy of 97% on validation data and 96% on test data) compared to previous studies for automated glaucoma detection. The second DL model used in the pilot study also showed promising outcomes (AUC 0.99 and accuracy of 98.6%) to detect glaucoma compared to two pre-trained models. In combination, the result of the two studies strongly suggests the four features and the cross-sectional ONH cup area trained using deep learning have a great potential for use as an initial screening tool for glaucoma which will assist clinicians in making a precise decision.</jats:p
Morphology of two dimensional fracture surface
We consider the morphology of two dimensional cracks observed in experimental
results obtained from paper samples and compare these results with the
numerical simulations of the random fuse model (RFM). We demonstrate that the
data obey multiscaling at small scales but cross over to self-affine scaling at
larger scales. Next, we show that the roughness exponent of the random fuse
model is recovered by a simpler model that produces a connected crack, while a
directed crack yields a different result, close to a random walk. We discuss
the multiscaling behavior of all these models.Comment: slightly revise
Do EnChroma glasses improve color vision for colorblind subjects?
The commercialization of EnChroma glasses has generated great expectations for
people to be able to see new colors or even correct color vision deficiency (CVD). We
evaluate the effectiveness of these glasses using two complementary strategies for the first
time. The first consists of using the three classical types of tests — recognition, arrangement
and discrimination — with and without glasses, with a high number of individuals. In the
second, we use the spectral transmittance of the glasses to simulate the appearance of stimuli
in a set of scenes for normal observers and observers with CVD. The results show that the
glasses introduce a variation of the perceived color, but neither improve results in the
diagnosis tests nor allow the observers with CVD to have a more normal color vision.Spanish State Agency of Research (AEI); Ministry for Economy, Industry and
Competitiveness (MIMECO) (Grant numbers FIS2017-89258-P and DPI 2015-64571-R);
European Union FEDER (European Regional Development Funds)
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