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OBJECTIVE. The purpose of this study was to investigate whether early kinetic parameters derived from ultrafast dynamic contrast-enhanced MRI (DCE-MRI) using compressed sensing are associated with prognostic factors for breast cancer. MATERIALS AND METHODS. We evaluated 201 consecutive women (mean age, 54.6 years) with breast cancer (168 invasive, 33 ductal carcinoma in situ) who underwent both ultrafast DCE-MRI using compressed sensing (temporal resolution, 4.7 seconds; spatial resolution, 0.8 × 1.1 × 0.9 mm) and surgery between 2018 and 2019. Early kinetic parameters (time to enhancement [TTE] and maximum slope [MS]) were measured in breast lesions by two radiologists using a software program and were correlated with histopathologic prognostic factors. The Mann-Whitney U test and linear regression analysis were used. RESULTS. The median TTE and MS values for breast cancer were 11.9 seconds and 7.7%/s, respectively. The median MS was significantly larger in invasive cancer lesions than in ductal carcinoma in situ lesions (8.4%/s vs 4.7%/s, p 2 cm) (p = .048) and estrogen receptor-negative status (p < .001) were significantly associated with a shorter TTE. A higher histologic grade (grade 3) (p = .01) was significantly associated with a larger MS. We observed excellent interobserver agreement between two readers in the measurements of TTE and MS (intraclass correlation coefficients, 0.943 and 0.890, respectively). CONCLUSION. Ultrafast MRI-derived early enhancement parameters, such as TTE and MS, are associated with histopathologic prognostic factors in women with breast cancer.

BACKGROUND: Detecting local tumor recurrence from post-treatment changes in head and neck cancer (HNC) remains a challenge. Based on the hypothesis that post-therapeutically altered tissue is bradytroph, lower perfusion values are expected in perfusion CT (PCT) while higher perfusion values are expected in recurrent malignant tissue. OBJECTIVES: This prospective study investigates PCT for post-treatment recurrent HNC detection with a maximum slope algorithm. METHODS: A total of 80 patients who received PCT of the head and neck for post-therapy follow-up, of which 63 had no tumor recurrence and 17 presented a histopathologically confirmed recurrence were examined. Regions of interest were placed in the location of the initial tumor, in reference ipsilateral nuchal muscle tissue and the corresponding internal carotid artery. Perfusion was calculated using a single-input maximum slope algorithm. RESULTS: With PCT, recurrent HNC can be differentiated from post-treatment tissue (p 0.05). CONCLUSIONS: PCT in combination with a commercially available maximum slope algorithm offers radiologists a reliable imaging tool to detect recurrent head and neck cancer within post-therapeutically altered tissue.

OBJECTIVE To develop a method based on CT angiography and the maximum slope model (MSM) to measure regional lung perfusion in anesthetized ponies. ANIMALS 6 ponies. PROCEDURES Anesthetized ponies were positioned in dorsal recumbency in the CT gantry. Contrast was injected, and the lungs were imaged while ponies were breathing spontaneously and while they were mechanically ventilated. Two observers delineated regions of interest in aerated and atelectatic lung, and perfusion in those regions was calculated with the MSM. Measurements obtained with a computerized method were compared with manual measurements, and computerized measurements were compared with previously reported measurements obtained with microspheres. RESULTS Perfusion measurements obtained with the MSM were similar to previously reported values obtained with the microsphere method. While ponies were spontaneously breathing, mean ± SD perfusion for aerated and atelectatic lung regions were 4.0 ± 1.9 and 5.0 ± 1.2 mL/min/g of lung tissue, respectively. During mechanical ventilation, values were 4.6 ± 1.2 and 2.7 ± 0.7 mL/min/g of lung tissue at end expiration and 4.1 ± 0.5 and 2.7 ± 0.6 mL/min/g of lung tissue at peak inspiration. Intraobserver agreement was acceptable, but interobserver agreement was lower. Computerized measurements compared well with manual measurements. CLINICAL RELEVANCE Findings showed that CT angiography and the MSM could be used to measure regional lung perfusion in dorsally recumbent anesthetized ponies. Measurements are repeatable, suggesting that the method could be used to determine efficacy of therapeutic interventions to improve ventilation-perfusion matching and for other studies for which measurement of regional lung perfusion is necessary.

This work investigates the fire line evolution in canyon fire spread by analytical and experimental means. The purpose is to understand the mechanism of fire spread acceleration associated with eruptive fire in canyon terrain. A symmetrical model canyon is used for experiments, and in each test the fire is initiated by a point ignition using dead pine needles as the fuels. By experimental observations and data, three distinct types of fire line contour are identified under different central slope angles (the angle between the canyon centerline and the horizontal ground), resulting in different variation modes of rate of spread along the canyon centerline. It is found that the trace of fire head deviates from the line of maximum slope for non-zero central slope angles, and such a deviation increases with increasing central slope angle. The fire spread acceleration associated with eruptive fire occurs when the central slope angle reaches a certain critical value. Experimental data confirm that under higher slope conditions, the significant interaction between the two lateral flame fronts induces marked convective heating ahead of the flame front, which is inferred to be the potential mechanisms of eruptive fire in canyon topography. A model analysis further elucidates how the deflection of the trace of fire head, induced by the fire interaction effect, influences the acceleration of fire spread under higher slope conditions.

Excessive longitudinal deceleration and acceleration reduce driving comfort and increase safety risk. There is a dearth of research, however, on how geometric design characteristics, especially complex alignments and their adjacent segments, affect deceleration and acceleration. The Tongji University driving simulator was used to collect vehicle operation data. Deceleration and acceleration values were measured and classified as deceleration, near-cruising and acceleration. A random parameter multinomial logistic regression model was used to reflect the relationships between drivers’ deceleration and acceleration and the geometric alignments of a mountainous freeway. Vehicle speed was treated as a random slope parameter to account for the heterogeneity among subjects. Model results showed deceleration and acceleration were significantly influenced by the fixed effects of maximum curvature in the following 50 m, difference between maximum and minimum slope in the preceding 100 m, maximum slope change in the following 400 m, and maximum curvature in the preceding 50 m. These findings can assist in developing safer design and evaluation standards for mountainous freeways.

Purpose To prospectively compare the capability of dynamic first-pass contrast-enhanced (CE) perfusion MR imaging with ultra-short TE and area-detector CT (ADCT), analyzed with the same mathematical methods, and that of FDG-PET/CT for diagnosis and management of solitary pulmonary nodules (SPNs). Methods and materials Our institutional review board approved this study and written informed consent was obtained from all subjects. A total 57 consecutive patients with 71 nodules prospectively underwent dynamic CE-perfusion ADCT and MR imaging with ultra-short TE, FDG-PET/CT, as well as microbacterial and/or pathological examinations. The nodules were classified into malignant nodules (n = 45) and benign nodules (n = 26). Pulmonary arterial, systemic arterial and total perfusions were determined by means of dual-input maximum slope models on ADCT and MR imaging and maximum values of standard uptake values (SUVmax) on PET/CT. Receiver operating characteristic (ROC) analysis was performed for each index, and sensitivity, specificity and accuracy were compared by McNemar's test. Results Areas under the curve (Azs) of total perfusion on ADCT (Az = 0.89) and MR imaging (Az = 0.88) were significantly larger than those of systemic arterial perfusion and MR imaging (p Conclusion Dynamic CE-perfusion MR imaging with ultra-short TE and ADCT and have similar potential capabilities, and are superior to FDG-PET/CT in this setting.

A diode-pumped MoS2 passively Q-switched Nd:Gd0.69Y0.3NbO4 laser at 1066 nm was demonstrated for the first time. The maximum continuous (CW) wave output power of 1.77 W was obtained when the absorbed pump power was 7.28 W and the transmission of flat output coupler was 25%. The maximum slope efficiency reached 33.3%. The pulsed laser with high repetition rate was obtained when the two-dimensional (2D) MoS2 material was used as the saturable absorber. The highest repetition rate and the narrowest pulse width were reached 112 kHz and 532 ns, respectively.

The Tm3+/Ho3+-SrLaGa3O7 crystal was grown using the Czochralski (CZ) method. The absorption spectra, the fluorescence spectra around 2.0 μm and energy-transfer (ET) schemes between Tm3+ ions and Ho3+ ions has been studied. The lasing performance of Tm3+/Ho3+-SrLaGa3O7 crystal for a-cut and c-cut pumped by a fiber-coupled laser diode laser are presented in this paper. The maximum output powers of 6.15 W for a-cut crystal at 2041 nm and 2.51 W for c-cut crystal at 2044 nm have been obtained, respectively. The maximum slope efficiency in terms of absorbed pump power nearly reached 36.5% for the a-cut crystal and about 18.8% for the c-cut crystal. In addition, the width of tuning can reach about 450 nm, suggesting the potential of these crystals for ultrashort pulse generation by mode-locking.

Using data from the Sloan Digital Sky Survey Moving Object Catalog, we study color as a function of size for C-complex families in the Main Asteroid Belt to improve our understanding of space weathering of carbonaceous materials. We find two distinct spectral slope trends: Hygiea-type and Themis-type. The Hygiea-type families exhibit a reduction in spectral slope with increasing object size until a minimum slope value is reached and the trend reverses with increasing slope with increasing object size. The Themis family shows an increase in spectral slope with increasing object size until a maximum slope is reached and the spectral slope begins to decrease slightly or plateaus for the largest objects. Most families studied show the Hygiea-type trend. The processes responsible for these distinct changes in spectral slope affect several different taxonomic classes within the C-complex and appear to act quickly to alter the spectral slopes of the family members., Comment: 13 pages, 6 figures, 1 table, to be published in the Astronomical Journal

OBJECTIVE To evaluate the effect of contrast medium injection rate on CT-derived renal perfusion estimates obtained with the maximum slope method in healthy small dogs. ANIMALS 6 healthy sexually intact male purpose-bred Beagles. PROCEDURES All dogs underwent CT perfusion analysis 3 times in a crossover design, receiving a different contrast medium injection rate (1.5, 3.0, and 4.5 mL/s) each time, with a 1-week interval between imaging sessions. All CT images were obtained at the level of the left renal hilus. The time to peak aortic enhancement (TPAE) and time to initial renal venous enhancement (TIRVE) were measured from time-attenuation curves. The renal CT perfusion estimates (blood flow and blood volume) were estimated by use of the maximum slope method, which assumes no venous outflow of contrast medium during CT perfusion analysis. RESULTS The TPAE occurred at or before the TIRVE at all injection rates. Median values of estimated blood flow and blood volume did not differ significantly among injection rates. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the assumption of no venous outflow of contrast medium during renal CT perfusion analysis with the maximum slope method was satisfied for all 3 contrast medium injection rates in the evaluated dogs. A low injection rate may be more practical than higher injection rates that require large catheters for CT perfusion analysis in small dogs such as Beagles.

Background Ultrafast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)-derived kinetic parameters have demonstrated at least equivalent accuracy to standard DCE-MRI in differentiating malignant from benign breast lesions. However, it is unclear if they have any efficacy as prognostic imaging markers. The aim of this study was to investigate the relationship between ultrafast DCE-MRI-derived kinetic parameters and breast cancer characteristics. Methods Consecutive breast MRI examinations between February 2017 and January 2018 were retrospectively reviewed to determine those examinations that meet the following inclusion criteria: (1) BI-RADS 4–6 MRI performed on a 3T scanner with a 16-channel breast coil and (2) a hybrid clinical protocol with 15 phases of ultrafast DCE-MRI (temporal resolution of 2.7–4.6 s) followed by early and delayed phases of standard DCE-MRI. The study included 125 examinations with 142 biopsy-proven breast cancer lesions. Ultrafast DCE-MRI-derived kinetic parameters (maximum slope [MS] and bolus arrival time [BAT]) were calculated for the entire volume of each lesion. Comparisons of these parameters between different cancer characteristics were made using generalized estimating equations, accounting for the presence of multiple lesions per patient. All comparisons were exploratory and adjustment for multiple comparisons was not performed; P values Results Significantly larger MS and shorter BAT were observed for invasive carcinoma than ductal carcinoma in situ (DCIS) (P P = 0.008, respectively). Significantly shorter BAT was observed for invasive carcinomas with more aggressive characteristics than those with less aggressive characteristics: grade 3 vs. grades 1–2 (P = 0.025), invasive ductal carcinoma vs. invasive lobular carcinoma (P = 0.002), and triple negative or HER2 type vs. luminal type (P Conclusions Ultrafast DCE-MRI-derived parameters showed a strong relationship with some breast cancer characteristics, especially histopathology and molecular subtype.

Background The hemodynamics of congestion areas in the right lobe graft after living donor liver transplantation (LDLT) remains unclear. The aim of this study was to elucidate the hemodynamics of congestion areas in the right lobe graft after LDLT using computed tomography (CT) perfusion imaging and the dual-input maximum slope method. Methods Sixteen recipients underwent CT perfusion of the liver and portal phase abdominal to pelvic CT 1week after LDLT using a right lobe graft. The attenuation of segments V and VIII on the portal venous phase abdominal to the pelvic CT scan was classified into 3 categories: hyperattenuation, iso-attenuation, and hypoattenuation. Mean arterial blood flow (AF, mL/min/100 mL tissue), portal blood flow (PF, mL/min/100 mL tissue), and perfusion index (%) [PI = AF/(AF + PF) × 100] were compared between the hyperattenuation group and iso-attenuation group. The independent t test was used for these statistical analyses. Results On the portal phase abdominal scan, 15 segments, 16 segments, and 1 segment showed hyperattenuation, iso-attenuation, and hypoattenuation, respectively. The mean AF and PI of the hyperattenuation group (44.4 ± 24.4, 30.2 ± 13.5) were significantly higher than those of the iso-attenuation group (28.0 ± 7.8, 19.9 ± 6.2) (P Conclusions The congested liver segments showed high AF and high PI on CT perfusion imaging. This method enables the feasible quantification of the hemodynamics and the description of focal hemodynamic change in the graft after LDLT.

Populations are locked down during an epidemic to slow down the rate of infection so that epidemic trajectory is "flattened". This helps to keep cases at a manageable level. Given the enormous economic damage and misery caused by a lockdown, it is imperative to keep the lockdown period limited. A lockdown is useful only if it can be ensured that after the lockdown is lifted, the epidemic trajectory does not rise sharply again. We present here the results from a mathematical model of the epidemic which examines how the timing, strength and duration of the lockdown affects the post-lockdown epidemic trajectory. Our results show the following:A early lockdown (imposed when less than 1% of the population has been infected), of any reasonable duration, cannot prevent the return of the epidemic when the lockdown is lifted. The curve starts climbing soon after lifting the lockdown and reaches a peak of the same height as the no-lockdown curveThe post-lockdown trajectory can be flattened only if the lockdown is imposed after about 10% of the population has recovered after infection.The slope of the post-lockdown epidemic curve depends on the level of immunity built up in the population before and during the lockdown period. Application of lockdown around the inflexion point of the epidemic curve (the point of maximum slope of the curve) ensures that the post-lockdown curve is also flattened.

The research location is in the PPSDM Geominerba field campus. The campus is located in Padalarang, West Java that is surrounded by the open-pit mining of limestone and marble. This limestone was formed in Oligo-Miocene of Rajamandala Formation. The research objective was to determine the condition of the slopes around the campus based on geomechanical characteristics. Based on field observations, the slope angle in the area is dominated by steep slopes. The rock hardness level is dominated by hard rock with a hardness ranging from 50-100 MPa. Rock Mass Rating shows that the are a is dominated by good rocks. While the S lope Mass Rating calculation show that the maximum slope angle is between 52-75 ° . L evel of deformation and intensive weathering process will reduce the strength of the rock in the future. Several rock fall occurrences on this research area support this assumption . Yet , some local open pit mining area activity near the toe hill of the area need to be concerned regarding the effect of the local rock fall occurrences.

To assess the diagnostic utility of different perfusion algorithms for the detection of angiographical terial spasm.During a 2-year period, 45 datasets from 29 patients (54.2±10,75y, 20F) with suspected cerebral vasospasm after aneurysmal subarachnoid hemorrhage were included. Volume Perfusion CT (VPCT), Non-enhanced CT (NCT) and angiography were performed within 6hours post-ictus. Perfusion maps were generated using a maximum slope (MS) and a deconvolution-based approach (DC). Two blinded neuroradiologists independently evaluated MS and DC maps regarding vasospasm-related perfusion impairment on a 3-point Likert-scale (0=no impairment, 1=impairment affecting50%, 2=impairment affecting50% of vascular territory). A third independent neuroradiologist assessed angiography for presence and severity of arterial narrowing on a 3-point Likert scale (0=no narrowing, 1=narrowing affecting50%, 2=narrowing affecting50% of artery diameter). MS and DC perfusion maps were evaluated regarding diagnostic accuracy for angiographical arterial spasm with angiography as reference standard. Correlation analysis of angiography findings with both MS and DC perfusion maps was additionally performed. Furthermor, the agreement between MS and DC and inter-reader agreement was assessed.DC maps yielded significantly higher diagnostic accuracy than MS perfusion maps (DC:AUC=.870; MS:AUC=.805; P=0.007) with higher sensitivity for DC compared to MS (DC:sensitivity=.758; MS:sensitivity=.625). DC maps revealed stronger correlation with angiography than MS (DC: R=.788; MS: R=694;=0.001). MS and DC showed substantial agreement (Kappa=.626). Regarding inter-reader analysis, (almost) perfect inter-reader agreement was observed for both MS and DC maps (Kappa≥981).DC yields significantly higher diagnostic accuracy for the detection of angiographic arterial spasm and higher correlation with angiographic findings compared to MS.

To assess the diagnostic value and contribution to BI-RADS categorisation of initial enhancement on ultra-fast DCE-MRI for differentiating malignant and benign breast lesions. The institutional review board approved this study, and written informed consent was obtained from each participant. Both ultra-fast DCE-MRI for initial enhancement analysis and conventional MRI were performed on 200 subjects with a total of 215 lesions (147 malignant and 68 benign). BI-RADS categorisation of enhancing lesions was performed using the conventional MRI. Two initial enhancement measures, time to enhancement (TTE) and maximum slope (MS), were derived from the ultra-fast DCE-MRI. Diagnostic performance and the additional diagnostic value of adding TTE and MS to BI-RADS were evaluated. Both TTE and MS showed significant differences between malignant and benign breast lesions in masses (TTE, p

The Small Punch Test (SPT) is a miniaturized test to characterize the mechanical properties of the materials. The load-displacement curve obtained by this test does not directly provide the material parameters, and linear correlations between data obtained from SPT curve and each mechanical property are necessary. The main difficulty of these correlation methods is the high level of scattering showed when analyzing a wide set of materials in the same study.In this paper, a finite element analysis focused on steel alloys was performed to understand the specimen behavior in the early stages of the SPT. Present methods to correlate the material yield strength with the data obtained from the SPT curve were also analyzed via this FEM study to discover the meaning of the current correlation scattering for this mechanical property. This numerical research also proved the accuracy of the proposed correlation method for the yield strength via the SPT. The maximum slope of zone I (Slopeini) of the SPT curve showed an accurate correlation with this mechanical property.Focusing on steel alloys, experimental tensile tests and SPT's were performed to validate the numerical analysis and to demonstrate the suitability of the proposed Slopeini versus yield strength correlation method. Keywords: Small Punch Test, SPT, Yield strength

Purpose The aims were to analyze stiffness, ultimate force, and failure modes of a 2-piece zirconium dioxide (ZrO2) implant system. Methods Eleven 2-piece ZrO2 implants, each mounted with ZrO2 abutments plus bonded monolithic lithium disilicate (LS2) restorations, were grouped for 3.3 mm (A) and 4.1 mm (B) diameter samples. Quasi-static load was monotonically applied under a standardized test set-up (loading configuration according to DIN ISO 14801). The ultimate force was defined as the maximum force that implants are able to carry out until fracture; stiffness was measured as the maximum slope during loading. An unpaired t-test was performed between group A and B for ultimate force and stiffness (p Results Force-displacement curves revealed statistically homogenous inner-group results for all samples. Failure modes showed characteristic fractures at the neck configuration of the implants independent of the diameter. Mean stiffness was 1099 N/mm (± 192) for group A, and significantly lower compared to group B with 1630 N/mm (± 274) (p Conclusions The examined 2-piece ZrO2 implant system mounted to LS2-restorations seems to be a stable unit under in-vitro conditions with mechanical properties compared to loading capacity of physiological force. The metal-free implant reconstructions demonstrated high stiffness and ultimate force under quasi-static load for single tooth replacement under consideration of the dental indication of narrow and standard diameter implants.

The Indian Ocean humpback dolphin (Sousa plumbea), a common cetacean species in India, has a diverse vocal repertoire, which to date has not been described in detail. This study focused on analyzing their whistle vocalizations. Humpback dolphins were recorded off the Sindhudurg coast of Maharashtra, India, and 2,260 whistles were analyzed for their acoustic characteristics. Whistles spanned a wide frequency range between 2.3 kHz and 33.0 kHz, with durations ranging from 0.01 s to 1.60 s. Whistles were categorized into seven contour classes based on their qualitative properties. A classification and regression tree (CART) analysis was used to quantify variability between the seven contour classes using the measured acoustic features. Based on the CART analysis, frequency gradient, minimum slope, maximum slope, beginning and ending slope accounted for most variability between whistle types. CART resulted in an overall classification accuracy of 89.5%. This study provides a detailed description of acoustic features and qualitative properties of humpback dolphin whistles from the northwestern coast of India. Further comparisons of acoustic data from Sousa populations along the Indian coast are necessary to determine possible geographic variations in whistle characteristics and whether the variations are driven by environmental or genetic factors or a combination of both.

The work here presented is focused on defining the geometrical limitations in the manufacturing of metallic parts by the additive manufacturing (AM) technology named Laser Metal Deposition (LMD). AM techniques are often perceived by designers as able to produce parts of any level of complexity. Nevertheless, there exist limitations inherent to all AM processes, and in particular to the LMD, where geometrical distortions and other undesirable factors can be produced, this technique does not provide absolute freedom to fabricate any geometry. Part designers often lack of comprehension about these problems and their effect in the final products. The aim of this work is to approach this lack of knowledge via experimental inspection in order to quantify the geometrical limitations and identify the most common defects of the LMD. To this purpose, the research was focused in the study of inclined walls, experimentally depositing and measuring which is the maximum slope with which an inclined wall can be manufactured by LMD under different conditions

Purpose: To investigate the performance of a new semi-automatic method for analyzing the signal time-intensity curve (TIC) obtained by breast dynamic contrast enhancement (DCE)-MRI. Methods: In the conventional method, a circular region of interest was drawn manually onto the map reflecting the maximum slope of increase (MSI) to delineate the suspicious lesions. The mean TIC was determined subjectively as one of three different wash-out patterns. In the new method, the lesion area was identified semi-automatically. The mean TIC was categorized quantitatively. In addition to the MSI, other quantitative parameters were calculated, including the signal intensity slope (SIslope), initial percentage of enhancement (Einitial), percentage of peak enhancement (Epeak), early signal enhancement ratio (ESER), and second enhancement percentage (SEP). The performances were compared with receiver operating characteristic (ROC) analysis and Wilcoxon's test. Results: For TIC categorization results, the diagnostic accuracy rates were 61.54% with the traditional manual method and 76.92% with the new method. For the mean MSI values from the manual method, the accuracy was 63.41%. For the mean TIC derived using the semi-automatic method, the diagnostic accuracy were 82.05% for SIslope, 67.31% for MSI, 61.53% for Einitial, 64.75% for Epeak, 64.74% for ESER, and 52.56% for SEP, respectively. For the lesion regions identified by the semi-automatic method, the diagnostic accuracy for above mentioned parameters were 80.13%, 69.87%, 61.54%, 63.47%, 64.74% and 55.13%, respectively. Conclusion: With respect to the analysis of TIC from breast DCE-MRI, the results demonstrated that the new method increased the diagnostic accuracy, and should be considered as a supplementary tool for distinguishing benign and malignant lesions.

Results are presented for the solution of the problem of gas flow in a porous body with the presence of a temperature “step” in the range 1–100 of the non-dimensional heat-transfer coefficient, while accounting for longitudinal thermal conductivity. The problem was solved using the numerical finite difference method. Maximum slope angles were derived for temperature curves that can be used to obtain the thermal characteristics of high-compact heat transfer surfaces with the single-flow non-stationary method. Recommendations were provided regarding the range of applicability of the method, taking into account the new received results.

Objectives: Temperature dependent chemical shifts of important brain metabolites measured by localised 1H MRS were investigated to test how the use of incorrect prior knowledge on chemical shifts impairs the quantication of metabolite concentrations. Materials and methods: Phantom measurements on solutions containing 11 metabolites were performed on a 7 T scanner between 1 and 43 °C. The temperature dependence of the chemical shift differences was fitted by a linear model. Spectra were simulated for di erent temperatures and analysed by the AQSES program (jMRUI 5.2) using model functions with chemical shift values for 37 °C. Results: Large differences in the temperature dependence of the chemical shift differences were determined with a maximum slope of about ±7.5 × 10−4 ppm/K. For 32–40 °C, only minor quantification errors resulted from using incorrect chemical shifts, with the exception of Cr and PCr. For 1–10 °C considerable quantification errors occurred if the temperature dependence of the chemical shifts was neglected. Conclusion: If 1H MRS measurements are not performed at 37 °C, for which the published chemical shift values have been determined, the temperature dependence of chemical shifts should be considered to avoid systematic quantification errors, particularly for measurements on animal models at lower temperatures.

Analytical relations to describe experimentally measured traction-separation laws are often expressed in dimensionless quantities. The traction and the separation are commonly normalized using the cohesive strength and a length measure, respectively. The ratio between the fracture energy and the cohesive strength is often used as a length measure. An alternative length measure is the ratio between the cohesive strength and the maximum slope of the traction-separation law. A relation between these two length measures are established. To illustrate the implications on cohesive laws, three existing cohesive laws are rewritten using the alternative normalization. As a result it is shown that the number of unknown material parameters can be reduced. One of the derived dimensionless cohesive law is validated against experimental uniaxial tension and compression load-deformation data of different sample sizes and different quasi-brittle materials, i.e. concrete and paperboard. A good fit of the cohesive law is shown to all the investigated data. These findings indicate that the derived normalized cohesive law is independent of material directions, moisture contents and sample size.

Producción Científica, Debris cones are a very common landform in temperate high mountains. They are the most representative examples of the periglacial and nival processes. This work studies the dynamic behavior of two debris cones (Cone A and Cone B) in the Picos de Europa, in the north of the Iberian Peninsula. Their evolution was measured uninterruptedly throughout each August for 10 years (2009–2018) using the Terrestrial Laser Scanning (TLS) technique. The observations and calculations of the two debris cones were treated independently, but both showed the same behavior. Therefore, if these results are extrapolated to other debris cones in similar environments (temperate high mountain), they should show behavior similar to that of the two debris cones analyzed. Material falls onto the cones from the walls, and transfer of sediments follows linear trajectories according to the maximum slope. In order to understand the linear evolution of the two debris cones, profiles were created along the maximum slope lines of the Digital Elevation Model (DEM) of 2009, and these profile lines were extrapolated to the remaining years of measurement. In order to determine volumetric surface behavior in the DEMs, each year for the period 2009–2018 was compared. In addition, the statistical predictive value for position (Z) in year 2018 was calculated for the same planimetric position (X,Y) throughout the profiles of maximum slopes. To do so, the real field data from 2009–2017 were interpolated and used to form a sample of curves. These curves are interpreted as the realization of a functional random variable that can be predicted using statistical techniques. The predictive curve obtained was compared with the 2018 field data. The results of both coordinates (Z), the real field data, and the statistical data are coherent within the margin of error of the data collection., Fondo Europeo de Desarrollo Regional - Agencia Estatal de Investigación (grant TIN2016-76843-C4-2-R), Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (grant CGL2015-68144-R)

BACKGROUND AND OBJECTIVES To investigate the performance of texture analysis based on enhancement kinetic parametric maps derived from breast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in discriminating benign from malignant tumors. METHODS A total of 192 cases confirmed by histopathology were retrospectively selected from our Picture Archiving and Communication System, including 93 benign and 99 malignant tumors. Lesion areas were delineated semi-automatically, and six kinetic parametric maps reflecting the perfusion information were generated, namely the maximum slope of increase (MSI), slope of signal intensity (SIslope ), initial percentage of peak enhancement (Einitial ), percentage of peak enhancement (Epeak ), early signal enhancement ratio (ESER), and second enhancement percentage (SEP) maps. A total of 286 texture features were extracted from those quantitative parametric maps. The Student t test or Mann-Whitney U test was used to select features that were statistically significantly different between the benign and malignant groups. A support vector machine was employed with a leave-one-out cross-validation method to establish the classification model. Classification performance was evaluated according to the receiver operating characteristic (ROC) theory. RESULTS The areas under ROC curves (AUCs) indicating the diagnostic performance were 0.925 for MSI, 0.854 for SIslope , 0.756 for Einitial , 0.923 for Epeak , 0.871 for ESER and 0.881 for SEP. Significant differences in AUCs were found between Einitial vs MSI, Einitial vs Epeak and Einitial vs SEP (P

Purpose To evaluate the diagnostic performance of a multiparametric approach to breast lesions including apparent diffusion coefficient (ADC) from diffusion-weighted images (DWI), maximum slope (MS) from ultrafast dynamic contrast enhanced (UF-DCE) MRI, lesion size, and patient's age. Materials and methods In total, 96 lesions (73 malignant, 23 benign) were evaluated. UF-DCE MRI was acquired using a prototype 3D-gradient-echo volumetric interpolated breath-hold examination (VIBE) with compressed sensing. Images were obtained up to 1 min after gadolinium injection. MS was calculated as the percentage relative enhancement/s. An ADC map was automatically generated from DWI at b = 0 and b = 1000 s/mm2. MS and ADC values were measured by two radiologists independently. Interrater agreement was evaluated using intraclass correlation coefficients. Univariate and multivariate logistic regression analyses were performed using MS, ADC, lesion size, and the patient's age. The parameters of the prediction model were generated from the results of the multivariate logistic regression analysis. Area under the curve (AUC) was used to compare diagnostic performance of the prediction model and each parameter. Results Interrater agreements on MS and ADC were excellent (ICC 0.99 and 0.88, respectively). MS, ADC, and patient's age remained as significant parameters after univariate and multivariate logistic regression analysis. The prediction model using these significant parameters yielded an AUC of 0.90, significantly higher than that of MS (AUC 0.74, p = 0.01). The AUCs of ADC, MS, patient's age were 0.87, 0.74 and 0.73, respectively. Conclusions A multiparametric model using ADC from DWI, MS from UF-DCE MRI, and patient's age showed excellent diagnostic performance, with greater contribution of ADC. Combining DWI and UF-DCE MRI might reduce scanning time while preserving diagnostic performance.

Purpose To investigate whether the additional use of ultrafast MRI can improve the diagnostic performance of conventional dynamic contrast-enhanced MRI (DCE-MRI) in evaluating MRI-detected lesions in breast cancer patients. Methods This retrospective study enrolled 101 consecutive breast cancer patients with 202 breast lesions (62 benign and 140 malignant) who underwent preoperative DCE-MRI with ultrafast imaging (9 image sets with 6.5-second temporal resolution). Two reviewers assessed the BI-RADS categories of breast lesions using conventional DCE-MRI and assessed the following parameters using the ultrafast MRI: initial enhancement phase, maximum relative enhancement, slope, and maximum slope (slopemax) on the kinetic curve. Interobserver agreement was analyzed between the two reviewers. The ultrafast MRI parameters were compared between benign and malignant tumors, and cut-off values were determined. For 97 additional MRI-detected lesions, the BI-RADS category was re-assessed using cut-off values, and the diagnostic performance was compared between the conventional DCE-MRI and the combined conventional and ultrafast DCE-MRI. Results All ultrafast MRI parameters differed significantly between malignant and benign tumors (p 9.8%/sec), the specificity of conventional DCE-MRI was significantly increased (29.4% vs 64.7%, p Conclusions The additional use of ultrafast MRI can improve the specificity of conventional DCE-MRI when evaluating MRI-detected masses in breast cancer patients.

Railway systems are an important means of transportation for both people and goods. Their safety, reliability, efficiency and effectiveness is pursued by mandatory technical standards concerning both design criteria and test procedures. One of the most important European standards to be fulfilled is EN 50553 concerning Running Capability in case of fire on board of rolling stock. One of the aspects that could have to be verified according to this standard consists in the capability of trains to continue providing minimum performance levels for a minimum amount of time even when parts of the propulsion systems incur in a fault due to a fire. This paper analyses and comments such requirement, illustrating how the manufacturers can exploit the limited minimum operation time required to increase the maximum slope that the train can overcome. In particular, the documents to be provided by the applicant to permit the body in charge to verify the compliancy will be discussed.

Through the analysis of driving stability of the vehicle on combined horizontal and vertical curves (CHVC), the safety model based on vehicle-road coordination was established with the critical state of accident as the limited condition. The influence of various factors on the design parameters such as the minimum radius and the maximum slope length were discussed. The safety model showed that the minimum radius of CHVC was proportional to the driving speed and road gradient, but inversely proportional to the value of the superelevation and crosswise affixing coefficient. Besides, the maximum slope length of CHVC was proportional to the road rolling resistance coefficient and slip ratio, but it was inversely proportional to driving speed, road gradient, and vehicle type. Furthermore, the maximum slope length was less affected by the superelevation. In addition, in order to improve the safety level of mountainous roads, this paper discussed the threshold value of the design index of CHVC considering the actual operating speed of the vehicle.

We present the absorption spectroscopy and continuous-wave laser operation of Tm:YLF at cryogenic temperatures. At 100 K, a maximum output power of 2.55 W corresponding to a maximum slope efficiency of 22.8% is obtained using 15% output coupling transmission. The output laser wavelength is centered at 1877 nm for Elc.

A trapped air pocket can cause a partial air lock in the top of a hump pipe zone. It increases the resistance and decreases the hydraulic cross section, as well as the capacity of the water supply pipeline. A hydraulic model experiment is conducted to observe the deflection and movement of the trapped air pocket in the hump pipe zone. For various pipe flow velocities and air volumes, the head losses and the equilibrium slope angles are measured. The extra head losses are also obtained by reference to the original flow without the trapped air pocket. Accordingly, the equivalent sphere model is proposed to simplify the drag coefficients and estimate the critical slope angles. To predict the possibility and reduce the risk of a hump air lock, an empirical criterion is established using dimensional analysis and experimental fitting. Results show that the extra head losses increase with the increase of the flow velocity and air volume. Meanwhile, the central angle changes significantly with the flow velocity but only slightly with the air volume. An air lock in a hump zone can be prevented and removed by increasing the pipe flow velocity or decreasing the maximum slope of the pipe.

To determine whether liver lobe-based DCE-MRI can be used to detect the presence and Child-Pugh class of hepatitis B-related cirrhosis.Fifty-six cirrhotic patients with hepatitis B and 20 healthy participants underwent liver DCE-MRI, and the positive enhancement integral (PEI), time to peak (TTP), maximum slope of increase (MSI) and maximum slope of decrease (MSD) of the left lateral liver lobe (LLL), left medial liver lobe (LML), right liver lobe (RL), and caudate lobe (CL) were measured and analysed statistically to evaluate cirrhosis.TTP values of the LLL, LML, RL and CL were positively correlated with the Child-Pugh class of cirrhosis (r=0.452 to 0.55, all p0.05). PEI values of the LLL, LML, RL and CL, as well as the MSI of the CL and the MSD of the RL, were inversely correlated with the Child-Pugh class (r=-0.349 to -0.72, all p0.05). PEI values of the LLL and CL, or TTP values of the RL had the most area under receiver operating characteristic curve (AUC) of 0.99 for identifying the presence of liver cirrhosis. The PEI of the RL had the largest AUC of 0.975 and 0.78 for distinguishing the Child-Pugh class A of cirrhosis from class B-C and class A-B of cirrhosis from class C, respectively.Liver lobe-based DCE-MRI parameters are associated with the presence and Child-Pugh class of hepatitis B-related cirrhosis.

Objective The aim of this study was to investigate the feasibility of multiphasic dynamic computed tomography (CT) scans in providing liver tissue perfusion characteristics using the dual maximum slope model in patients with liver cirrhosis and hepatocellular carcinoma (HCC). Materials and methods With institutional review board approval and acquisition of informed consent, we retrospectively analyzed the prospectively collected perfusion CT (PCT) data of 36 patients enrolled in a prospective clinical trial for pretherapeutic assessment of HCC. To obtain perfusion parameters including arterial liver perfusion (ALP), portal venous perfusion (PVP), and the hepatic perfusion index (HPI), 5-phase dynamic CT data sets with triple arterial phases including peak aortic and splenic enhancement information were selected from the PCT data sets. The PCT and 5-phase dynamic CT data sets extracted from the PCT data were analyzed using dedicated perfusion software based on the dual maximum slope model. Comparisons between the perfusion parameters of each method were performed using Wilcoxon signed rank test and intraclass correlation coefficients. Results The extraction of liver perfusion parameters from 5-phase dynamic CT scans was feasible using the dual maximum slope model, and no significant differences were observed between perfusion parameters obtained from 5-phase dynamic CT and from PCT in the liver parenchyma (ALP, P = 0.137; PVP, P = 0.110; HPI, P = 0.793) and in HCCs (ALP, P = 0.162; HPI, P = 0.131). Regarding intraclass correlation coefficients, excellent agreement was observed between perfusion parameters obtained using 5-phase dynamic CT and from PCT in both the liver parenchyma (ALP, 0.793; PVP, 0.831; HPI, 0.934) and in HCCs (ALP, 0.889; HPI, 0.943). Conclusions The extraction of liver perfusion parameters from 5-phase dynamic CT scans was feasible using the dual maximum slope model and provided comparable values to those obtained from PCT.

Here we developed a novel wavelength-switchable visible continuous-wave (CW) Pr3+:YLF laser around 670 nm. In single-wavelength laser operations, the maximum output powers of 2.60 W, 1.26 W, and 0.21 W, the maximum slope efficiencies of 34.7%, 27.3%, and 12.3% were achieved with good beam qualities (M2 < 1.6) at 670.4 nm, 674.2 nm, and 678.9 nm, respectively. Record-high output power (2.6 W) and record-high slope efficiency (34.7%) were achieved for the Pr3+:YLF laser operation at 670.4 nm. This is also the first demonstration of longer-wavelength peaks beyond 670 nm in the 3P1→3F3 transition of Pr3+:YLF. In multi-wavelength laser operations, the dual-wavelength lasings, including 670.1/674.8 nm, 670.1/679.1 nm, and 675.0/679.4 nm, were obtained by fine adjustment of one/two etalons within the cavity. Furthermore, the triple-wavelength lasings, e.g. 672.2/674.2/678.6 nm and 670.4/674.8/679.4 nm, were successfully demonstrated. Moreover, both the first-order vortex lasers (LG0+1 and LG0-1 modes) at 670.4 nm were obtained by off-axis pumping.

The aim of the current study was to develop a semi-automatic and quantitative method for the analysis of a time-intensity curve (TIC) from breast dynamic contrast-enhanced magnetic resonance imaging. The performance of the proposed method, based on the level set segmentation algorithm, was evaluated by comparison with the traditional method. In the traditional method, the lesion area is delineated manually and the corresponding mean TIC is classified subjectively as one of three washout patterns. In addition, only one quantitative parameter, the maximum slope of increase (MSI), is calculated. In the proposed method, the lesion region was determined semi-automatically and the corresponding mean TIC was categorized quantitatively. In addition to MSI, a number of quantitative parameters were derived from the mean TIC and lesion area, including signal intensity slope (SI(slope)), initial percentage of enhancement (E(initial)), percentage of peak enhancement (E(peak)), early signal enhancement ratio (ESER) and second enhancement percentage (SEP). Wilcoxon signed-rank test and receiver operating characteristic analyses were performed for statistical analysis. For TIC categorization the accuracy was 61.54% for the traditional method and 82.05% for the proposed method. Using the proposed method, mean curve accuracies were 84.0% for SI(slope), 66.7% for MSI, 66.0% for E(initial), 66.0% for E(peak), 68.0% for ESER and 44.9% for SEP. In the lesion region, the accuracies for the aforementioned parameters were 80.8, 65.4, 66.7, 62.2, 69.2 and 57.1%, respectively. Accuracy of the MSI value derived from the traditional method was 63.4%. Compared with the traditional method, the proposed semi-automatic method in the current study may provide results with a higher accuracy to differentiate benign and malignant lesions. Therefore, the proposed method should be considered as a supplementary tool for the diagnosis of breast lesions.

Cardiovascular disease is a factor that leads to mortality in the populations of industrialized countries, being the large arteries pathology the main cause of morbidity and death from such disease. A functional characteristic of arteries that is changed under pathological conditions is their wall stiffness. Early diagnosis of such arterial alterations may identify individual risks to clinical complications, allowing retardation of the pathological process. Some examples of non-invasive methods of arterial stiffness assessment are the pulse wave velocity (PWV) and the pulse transit time (PTT). The present work proposes a PTT measurement system that estimates the time interval between the R wave of the QRS complex and the arrival of the pressure pulse wave at radial artery by using the bioimpedance technique to detect such arrival, instead of pressure transducers. Preliminary tests were made, taking two different points of the bioimpedance signal, and discounting or not the pre-ejection period. The PTT results, obtained from six volunteers, were on average close to the ones obtained by some other works using different techniques and measure points: 240 ms against 250 ms (literature) and 112 ms against 110 ms (literature). These values were collected by taking the interval between ECG peak and bioimpedance peak or bioimpedance maximum slope, respectively. Despite the need for more tests, the findings indicate that the system designed in this work may be used for arterial stiffness evaluation.

There are few optimizing methodologies that may guide the process of ramp design in underground mining; they contemplate designing the accesses and then completing the mine exploitation schedule, which does not reflect the development costs in the NPV of the project and relies on the engineer’s knowledge. The methodology presented in this paper focuses on the assisting the ramp design in underground mining using an optimization model that gives the operational costs associated with the accesses, during the development and the operation of the mine. Additionally, a sequence of construction is obtained as a complement of the design with a scheduling software. The methodology aims to obtain a design and sequence of the ramps and crosscuts configuration considering initial parameters that must be entered the optimization model such as production levels, maximum slope, curvature, construction costs, and transportation costs, among others. After applying the optimization model, the result is the identification of the points belonging to the ramp design, the ramp construction, and operation sequence and the total cost associated with the project. This result must be refined using CAD software to obtain the final configuration. When this methodology is applied to a case study, a gold and silver mine exploited using the Bench & Fill method, the results show that the optimization model can replicate the design obtained by the prefeasibility study of the project and provide additional design options that can reduce the total cost. The methodology provides operationally feasible solutions and can be used as a guide for the design of ramps in underground mining while reducing the time allocated to these tasks and delivering more than one design according to the initial parameters.

Cardiac arrest survival rate is strongly associated with high quality cardiopulmonary resuscitation (CPR), which includes chest compression (CC) rates above 100 min−1. Currently, defibrillator monitors use external hardware such as CPR assist pads to monitor CC rate and give feedback to the rescuer. The photoplethysmogram (PPG) provides information about the level of oxygen saturation in blood and can be easily recorded by a pulse oximeter in the fingertip. The aim of this study was to analyze the feasibility of using the finger PPG to monitor the presence and rate of CCs in out-of-hospital cardiac arrest (OHCA). The dataset used in the study consisted of 112 segments from 46 OHCA patients, with a total duration of 256 min and 27667 CCs. The method is based on the power spectral density analysis of 10 s segments of the PPG. CC presence was determined through thresholding, and CC rate was computed applying a maximum slope criterion. The dataset was divided patient-wise intro training (60%) and testing (40%) sets. For the test set the algorithm presented a sensitivity and a positive predictive value of 85.2% and 98.1% respectively for CC detection, a CC rate error of 2.8 (6.8)min−1 and 3.4% of the values with an error above 10%.

Background To explore the value of parameters of multiphase dynamic contrast-enhanced magnetic resonance imaging (MDCE-MRI) in the qualitative diagnosis of hepatic masses. Methods Eighty patients with hepatic masses were retrospectively analyzed. All the patients underwent MDCE-MRI at 3.0 T MR before treatment. Mean enhancement time (MET), positive enhancement integral (PEI), a maximum slope of increase (MSI), and a maximum slope of decrease (MSD) were measured. Results There were significant differences between benign and malignant hepatic masses with respect to MET, PEI, and MSI values. The PEI and MSI values between hemangiomas, hepatocellular carcinomas (HCCs), cholangiocarcinomas, and metastatic tumors had significant differences. The MSD value between metastatic tumors, HCCs, and hemangiomas were significantly different. The area under the curve (AUC) values of the receiver operator characteristic curves for MET, PEI, and MSI were 0.70, 0.72, and 0.80, respectively. The specificity of MET, PEI, and MSI were all 77%, and the sensitivities of MSI was the highest, of which was 82.40%. Logistic regression analysis showed the regression equation to be P = 1/[1 + e0.008 × 1 + 0.007 × 2–6.707], and taking the Youden index maximum points as a diagnostic point was 0.2946. Conclusion Some parameters of MDCE-MRI have significant roles in differentiating hepatic masses.

El riego por melgas es la modalidad de riego por superficie que se adapta mejor a los cultivos forrajeros en siembra directa, pero las condiciones de alta pendiente y baja velocidad de infiltración de la mayoría de los suelos del sur de Uruguay hacen difícil su adaptación cuando se pretende aplicar las recomendaciones de la bibliografía internacional. El objetivo del estudio fue determinar indicadores de desempeño del riego por melgas para los suelos del sur del Uruguay y plantear escenarios de optimización para identificar estrategias de manejo. Se instaló un ensayo de riego por melgas orientadas en el sentido de la máxima pendiente, variando la dirección entre grupo de melgas para minimizar la pendiente transversal. La buena conformación de los bordos de las melgas favoreció las medidas de los indicadores de desempeño. Para poder evaluar situaciones diferentes a las ensayadas a campo se planteó el uso del modelo WinSRFR. Los caudales con mejor desempeño fueron más bajos que los recomendados por la bibliografía internacional. Para el suelo evaluado y largo de ladera de 50-60 m el caudal 0,2 L/s/m tuvo la mejor respuesta a la optimización por tiempo de corte. El caudal 0,5 L/s/m alcanzó las mejores eficiencias con largos en el entorno de 170 m. El caudal 0,33 L/s/m podría ser la mejor solución en zonas donde la ladera tiene longitud variable, permitiendo alcanzar alta eficiencia de aplicación mediante la modificación del tiempo de riego. El modelo predijo muy bien el volumen infiltrado y escurrido.

To evaluate postexercise heart rate recovery (HRR) in adults born preterm.We studied the association between preterm birth and postexercise HRR in 545 adults (267 women) at 23.3 years of age (range 19.9-26.3 years). One hundred three participants were born early preterm (34 completed weeks), 178 late preterm (34-36), and 264 were full term (control group). HRR was calculated as change in heart rate (HR) 30 seconds and 60 seconds after cessation of submaximal step test and maximum HR slope during the first minute after.Mean peak HR was 159.5 bpm in the early preterm (P = .16 with controls), 157.8 bpm in the late preterm (P = .56), and 157.0 bpm in the control group. Mean HRR 30 seconds after exercise was 3.2 bpm (95% CI 1.1-5.2) lower in the early preterm group and 2.1 bpm (0.3-3.8) lower in the late preterm group than the full term controls. Mean 60s HRR was 2.5 (-0.1 to 5.1) lower in the early preterm group and 2.8 bpm (0.6-4.9) lower in the late preterm group. Mean maximum slope after exercise was 0.10 beats/s (0.02-0.17) lower in the early preterm group and 0.06 beats/s (0.00-0.12) lower in the late preterm group.Our results suggest reduced HRR after exercise in adults born preterm, including those born late preterm. This suggests altered reactivation of the parasympathetic nervous system, which may contribute to cardiovascular risk among adults born preterm.

Made available in DSpace on 2019-10-06T02:14:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-05-28 Coffee farms have been adopting the microterraces system, a technique that reduces the effect of the slope by moving the soil between the crop lines. In this way, all the mechanized operations can be carried out normally, except for harvesting, due to the work limitation of the harvesters, who work in areas with a maximum slope of 20%. One option is to use unilateral harvesters, which crop one side at a time; however, there has been no research on these microterrace machines to evaluate their performance and to compare it with those of the other harvesting methods in those regions. This study aimed to compare the mechanized harvest performance in the microterraces with the manual and semimechanized harvesting methods. The study was carried out in an agricultural area of the municipality of Ouro Fino / MG, Brazil, in a crop production site where the microterraces were built six years before the experiment. The treatments were assigned to a split-block design with seven repetitions and consisted of mechanized harvest-unilateral harvester with bag storage; manual harvest-regionally experienced workers; and semimechanized harvest-with portable breakers. Through an analysis of the times and movements, the operational efficiency and operational and effective field capabilities were measured. The adoption of microterraces allows the efficient mechanization of areas previously impossible to mechanize. The unilateral harvester is a potential tool for the partial replacement of manual labor in the harvest, performing a service equivalent to that of 23.68 manual workers and 10.55 manual workers in the semimechanized system. Sao Paulo State Univ, Lab Agr Machinery & Mechanizat, Dept Agr Engn, Jaboticabal, SP, Brazil Sao Paulo State Univ, Lab Agr Machinery & Mechanizat, Dept Agr Engn, Jaboticabal, SP, Brazil

We report on optical properties and lasing of YAG ceramics synthesized at IREE (Fryazino) and IEP (Ekaterinburg). On the best samples of ceramics lasing with the maximum slope efficiency of 40% was received. Specific losses in the ceramics are estimated. An analytical solution of the rate equations on one-pass optical amplification for laser ceramics with losses was obtained.

Spectroscopic properties of Er : LiLuF4 and Er : LiYF4 crystals in the spectral region near 1.5 μm and the lasing characteristics of these crystals under in-band pumping at a wavelength of 1522 nm are studied. With the Er : LiLuF4 crystal, the maximum slope efficiency with respect to the absorbed pump power was 44% at a wavelength of 1609 nm. Continuous-wave operation of an inband pumped Er : LiYF4 laser is obtained for the first time. The output power at a wavelength of 1606 nm was 58 mW with a slope efficiency of 21%.

Leadon, M., 2015. Beach slope and sediment-grain-size trends as a basis for input parameters for the SBEACH erosion model. Results from Storm-induced BEAch CHange (SBEACH) model calibration studies have provided new techniques and support for selection of model input parameters and interpretation of model output results. Beach and dune erosion analyses using the SBEACH erosion model in St. Johns County, Florida, demonstrated sensitivity of simulated erosion to changes of two model input parameters: sediment grain size and maximum slope prior to avalanching (MSPA). The MSPA parameter corresponds with the seaward slope of the dune or beach-berm erosion escarpment at the landward limit of the storm-induced erosion. Model calibration work demonstrated trends of these two model input parameters and of the sediment-transport rate coefficient K in relation to changes in beach slope. Evaluation of beach-slope values computed from county-wide topographic survey data in relation to the available mean sedim...

A common representation of a three dimensional object in computer applications, such as graphics and design, is in the form of a triangular mesh. In many instances, individual or groups of triangles in such representation need to satisfy spatial constraints that are imposed either by observation from the real world, or by concrete design specifications of the object. As these problems tend to be of large scale, choosing a mathematical optimization approach can be particularly challenging. In this paper, we model various geometric constraints as convex sets in Euclidean spaces, and find the corresponding projections in closed forms. We also present an interesting idea to successfully maneuver around some important nonconvex constraints while still preserving the intrinsic nature of the original design problem. We then use these constructions in modern first-order splitting methods to find optimal solutions.

We report laser operation of two Tb3+-activated gain media, Tb:LiYF4 and LiTbF4, in yellow or/and green spectral region. A record-high slope efficiency of 63% among Tb3+-lasers and maximum output power of 1.17 W (incident power of 2.79 W) at around 544 nm were obtained with a c-cut 15%Tb:LiYF4 crystal. The yellow laser characteristics in σ-polarization were studied. A slope efficiency of 21% at 582 nm was achieved. More importantly, we succeeded in laser operation of LiTbF4 for the first time to the best of our knowledge. Laser oscillation at around 544 nm yielded a maximum slope efficiency of 45%. This points toward the possibility of producing high-energy pulsed lasers using LiTbF4, which features a high active-ion concentration as well as relatively long lifetime.

We report laser operation of Pr:YAlO3 pumped by a frequency-doubled optically pumped semiconductor laser. Continuous-wave laser oscillations at around 622 nm, 662 nm, and 747 nm were demonstrated in plano-concave or/and plano-plano cavities. The maximum slope efficiencies were found to be 37%, 35%, and 59%, respectively, which are record-high values for Pr:YAlO3 lasers. Furthermore, lasing at 622 nm was demonstrated at room temperature for the first time to the best of our knowledge.