Prediction of long and short time rheological behavior in soft glassy materials

We present an effective time approach to predict long and short time rheological behavior of soft glassy materials from experiments carried out over practical time scales. Effective time approach takes advantage of relaxation time dependence on aging time that allows time-aging time superposition even when aging occurs over the experimental timescales. Interestingly experiments on variety of soft materials demonstrate that the effective time approach successfully predicts superposition for diverse aging regimes ranging from sub-aging to hyper-aging behaviors. This approach can also be used to predict behavior of any response function in molecular as well as spin glasses.Comment: 13 pages, 4 figure

Load-settlement modelling of axially loaded drilled shafts using CPT-based recurrent neural networks

The design of pile foundations requires good estimation of the pile load-carrying capacity and settlement. Design for bearing capacity and design for settlement have been traditionally carried out separately. However, soil resistance and settlement are influenced by each other, and the design of pile foundations should thus consider the bearing capacity and settlement inseparably. This requires the full load–settlement response of piles to be well predicted. However, it is well known that the actual load–settlement response of pile foundations can be obtained only by load tests carried out in situ, which are expensive and time-consuming. In this paper, recurrent neural networks (RNNs) were used to develop a prediction model that can resemble the full load–settlement response of drilled shafts (bored piles) subjected to axial loading. The developed RNN model was calibrated and validated using several in situ full-scale pile load tests, as well as cone penetration test (CPT) data. The results indicate that the developed RNN model has the ability to reliably predict the load–settlement response of axially loaded drilled shafts and can thus be used by geotechnical engineers for routine design practice

Intrapapillary vessel density using optical coherence tomography angiography in primary open-angle glaucoma and normal eyes

Background: Optical coherence tomography angiography (OCTA) is used to quantify optic nerve blood flow in patients with primary open-angle glaucoma (POAG). Intrapapillary vessel density (iVD) has a high diagnostic accuracy for differentiating healthy from glaucomatous eyes. We compared the iVD of patients with POAG with that of healthy controls in an Egyptian tertiary referral center. Methods: This cross-sectional study consecutively recruited patients with medically controlled POAG and age- and sex-matched healthy individuals. All study participants underwent a detailed medical history evaluation and comprehensive ophthalmic examination, with recording of the cup-to-disc ratio (C/D ratio) and intraocular pressure (IOP). Humphrey visual field evaluation using the standard 24-2 program was performed and global indices, including mean deviation (MD) and pattern standard deviation (PSD), were extracted. OCTA and spectral-domain (SD) OCT images were obtained. Average thickness of the retinal nerve fiber layer (RNFL) and thicknesses in the superior, inferior, nasal, and temporal quadrants were recorded. OCTA imaging was used to measure vessel density, and the automatically processed data for iVD were extracted. Results: We included 86 eyes, 43 in the POAG and 43 in the healthy control group, with male predominance in both groups and mean (standard deviation [SD]) ages of 42.1 (9.4) and 39.3 (9.6) years, respectively. The two groups were comparable in terms of mean age, sex ratio, laterality of the included eyes, and mean IOP (all P > 0.05). The mean (SD) C/D ratio, MD, and PSD were significantly higher in the POAG group than in the control group (all P < 0.01). The mean (SD) average RNFL thickness and RNFL thicknesses in the four quadrants were significantly less in glaucomatous eyes than in healthy control eyes (all P < 0.05). Eyes with POAG had a significantly lower mean (SD) iVD than healthy control eyes (P < 0.01). Linear regression analysis revealed a significant positive correlation between iVD and average RNFL thickness (r = + 0.52; P < 0.001) and a significant negative correlation between iVD and PSD (r = - 0.31; P = 0.042) in eyes with POAG. Conclusions: The structural, vascular, and functional parameters measured in this study deteriorated in eyes with POAG compared to controls. Significant circumpapillary RNFL thinning correlated well with reduced iVD in eyes with POAG. Similarly, a lower iVD detected using OCTA had a significant inverse correlation with PSD in the perimetry of eyes with POAG. Further studies with additional parameters and longer follow-up periods are required to verify our preliminary findings

Perturbative Study of Bremsstrahlung and Pair-Production by Spin-1/2 Particles in the Aharonov-Bohm Potential

In the presence of an external Aharonov-Bohm potential, we investigate the two QED processes of the emission of a bremsstrahlung photon by an electron, and the production of an electron-positron pair by a single photon. Calculations are carried out using the Born approximation within the framework of covariant perturbation theory to lowest non-vanishing order in \alpha. The matrix element for each process is derived, and the corresponding differential cross-section is calculated. In the non-relativistic limit, the resulting angular and spectral distributions and some polarization properties are considered, and compared to results of previous works.Comment: 15 pages, RevTex 4, 2 figures, submitted for publicatio

Efficacy of plant extracts in controlling wheat leaf rust disease caused by Puccinia triticina

AbstractThe efficacy of eight plant extracts (garlic, clove, garden quinine, Brazilian pepper, anthi mandhaari, black cumin, white cedar and neem) in controlling leaf rust disease of wheat was investigated in vitro and in vivo. In vitro, all treatments inhibited spore germination by more than 93%. Neem extract recorded 98.99% inhibition of spore germination with no significant difference from the fungicide Sumi-8 (100%). Under greenhouse conditions, seed soaking application in neem extract (at concentration of 2ml/L) resulted in 36.82% reduction in the number of pustules/leaf compared with the untreated control. Foliar spraying of plant extracts on wheat seedlings decreased the number of pustules/leaf. Foliar spraying of plant extracts four days after inoculation led to the highest resistance response of wheat plants against leaf rust pathogen. Spray application of wheat seedlings with neem, clove and garden quinine extracts, four days after inoculation with leaf rust pathogen completely prevented rust development (100% disease control) and was comparable with the fungicide Sumi-8. Foliar spray application of wheat plants at mature stage with all plant extracts has significantly reduced the leaf rust infection (average coefficient of infection, ACI) compared with the untreated control and neem was the most effective treatment. This was reflected on grain yield components, whereas the 1000-kernel weight and the test weight were improved whether under one- or two-spray applications, with two-spray application being more effective in this regard. Thus, it could be concluded that plant extracts may be useful to control leaf rust disease in Egypt as a safe alternative option to chemical fungicides

Patients over 65 years with Acute Complicated Calculous Biliary Disease are Treated Differently - Results and Insights from the ESTES Snapshot Audit

Background: Accrued comorbidities are perceived to increase operative risk. Surgeons may offer operative treatments less often to their older patients with acute complicated calculous biliary disease (ACCBD). We set out to capture ACCBD incidence in older patients across Europe and the currently used treatment algorithms. Methods: The European Society of Trauma and Emergency Surgery (ESTES) undertook a snapshot audit of patients undergoing emergency hospital admission for ACCBD between October 1 and 31 2018, comparing patients under and C 65 years. Mortality, postoperative complications, time to operative intervention, post-acute disposition, and length of hospital stay (LOS) were compared between groups. Within the C 65 cohort, comorbidity burden,mortality, LOS, and disposition outcomes were further compared between patients undergoing operative and non-operative management. Results: The median age of the 338 admitted patients was 67 years; 185 patients (54.7%) of these were the age of 65 or over. Significantly fewer patients C 65 underwent surgical treatment (37.8% vs. 64.7%, p\0.001). Surgical complications were more frequent in the C 65 cohort than younger patients, and the mean postoperative LOS was significantly longer. Postoperative mortality was seen in 2.2% of patients C 65 (vs. 0.7%, p = 0.253). However, operated elderly patients did not differ from non-operated in terms of comorbidity burden, mortality, LOS, or postdischarge rehabilitation need. Conclusions: Few elderly patients receive surgical treatment for ACCBD. Expectedly, postoperative morbidity, LOS, and the requirement for post-discharge rehabilitation are higher in the elderly than younger patients but do not differ from elderly patients managed non-operatively. With multidisciplinary perioperative optimization, elderly patients may be safely offered optimal treatment. Trial Registration ClinicalTrials.gov (Trial # NCT03610308)

Insolation-paced sea level and sediment flux during the early Pleistocene in Southeast Asia

Global marine archives from the early Pleistocene indicate that glacial-interglacial cycles, and their corresponding sea-level cycles, have predominantly a periodicity of ~ 41 kyrs driven by Earth’s obliquity. Here, we present a clastic shallow-marine record from the early Pleistocene in Southeast Asia (Cholan Formation, Taiwan). The studied strata comprise stacked cyclic successions deposited in offshore to nearshore environments in the paleo-Taiwan Strait. The stratigraphy was compared to both a δ18O isotope record of benthic foraminifera and orbital parameters driving insolation at the time of deposition. Analyses indicate a strong correlation between depositional cycles and Northern Hemisphere summer insolation, which is precession-dominated with an obliquity component. Our results represent geological evidence of precession-dominated sea-level fluctuations during the early Pleistocene, independent of a global ice-volume proxy. Preservation of this signal is possible due to the high-accommodation creation and high-sedimentation rate in the basin enhancing the completeness of the stratigraphic record

IMPaCT - Integration of Missions, Programs, and Core Technologies

IMPaCT enables comprehensive information on current NASA missions, prospective future missions, and the technologies that NASA is investing in, or considering investing in, to be accessed from a common Web-based interface. It allows dependencies to be established between missions and technology, and from this, the benefits of investing in individual technologies can be determined. The software also allows various scenarios for future missions to be explored against resource constraints, and the nominal cost and schedule of each mission to be modified in an effort to fit within a prescribed budget

Delayed solidification of soft glasses: New experiments, and a theoretical challenge

When subjected to large amplitude oscillatory shear stress, aqueous Laponite suspensions show an abrupt solidification transition after a long delay time tc. We measure the dependence of tc on stress amplitude, frequency, and on the age-dependent initial loss modulus. At first sight our observations appear quantitatively consistent with a simple soft-glassy rheology (SGR)-type model, in which barrier crossings by mesoscopic elements are purely strain-induced. For a given strain amplitude {\gamma}0 each element can be classified as fluid or solid according to whether its local yield strain exceeds {\gamma}0. Each cycle, the barrier heights E of yielded elements are reassigned according to a fixed prior distribution {\rho}(E): this fixes the per-cycle probability R({\gamma}0) of a fluid elements becoming solid. As the fraction of solid elements builds up, {\gamma}0 falls (at constant stress amplitude), so R({\gamma}0) increases. This positive feedback accounts for the sudden solidification after a long delay. The model thus appears to directly link macroscopic rheology with mesoscopic barrier height statistics: within its precepts, our data point towards a power law for {\rho}(E) rather than the exponential form usually assumed in SGR. However, despite this apparent success, closer investigation shows that the assumptions of the model cannot be reconciled with the extremely large strain amplitudes arising in our experiments. The quantitative explanation of delayed solidification in Laponite therefore remains an open theoretical challenge.Comment: 16 pages, 6 figures, to appear in Faraday Discussion

Resolving the Architecture and Early Evolution of a Forearc Basin (Georgia Basin, Canada) Using Detrital Zircon

Convergent-margin basins (CMBs) are commonly associated with active arcs, and hence are rich in detrital zircon (DZ) whose ages closely reflect the timing of deposition. Consequently, maximum depositional ages (MDA) from DZ geochronology can be employed to resolve the stratigraphy and evolution of CMBs. Herein, we use DZ to revise the internal architecture of the lower Nanaimo Group, which partially comprises the fill of the (forearc) Georgia (or Nanaimo) Basin. Maximum depositional ages and multi-dimensional scaling of DZ age distributions are employed to determine chronologic equivalency of strata and assess sediment provenance variability within the pre-existing lithostratigraphic framework. The results are compared to a recently developed sequence stratigraphic framework for the lower Nanaimo Group. The basal lithostratigraphic unit of the Nanaimo Group, the Comox Formation (Fm), comprises strata that are neither time correlative nor genetically related. The three lithostratigraphic units directly overlying the Comox Fm (Haslam, Extension, and Protection formations) comprise strata with similar genetic affinities and MDAs that indicate deposition of these units was not always sequential and locally was contemporaneous. Through this work, we provide an example of how MDAs from DZ geochronology in CMBs can resolve basin-scale stratigraphic relations, and identify chronological changes in sediment provenance