Smooth Index Research Articles

Inter-comparison of four models for smoothing satellite sensor time-series data to estimate vegetation phenology

Several models have been fitted in the past to smooth time-series vegetation index data from different satellite sensors to estimate vegetation phenological parameters. However, differences between the models and fine tuning of model parameters lead to potential differences, uncertainty and bias between the results amongst users. The current research assessed four techniques: Fourier analysis, asymmetric Gaussian model, double logistic model and the Whittaker filter for smoothing multi-temporal satellite sensor observations with the ultimate purpose of deriving an appropriate annual vegetation growth cycle and estimating phenological parameters reliably. The research used Level 3 Medium Resolution Imaging Spectrometer (MERIS, spatial resolution ~4.6km) Terrestrial Chlorophyll Index (MTCI) data over the years 2004 to 2006 composited at eight day intervals covering the Indian sub-continent. First, the four models were fitted to representative sample time-series of the major vegetation types in India, and the quality of the fit was analysed. Second, the effect of noise on model fitting was analysed by adding Gaussian noise to a standard profile. Finally, the four models were fitted to the whole study area to characterise variation in the quality of model fitting as a function of single and double vegetation seasons. These smoothed data were used to estimate the onset of greenness (OG), a major phenological parameter. The models were evaluated using the root mean square error (RMSE), Akaike Information Criteria (AIC), and Bayesian Information Criteria (BIC). The first test (fitting to representative sample time series) revealed the consistently superior performance of the Whittaker and Fourier approaches in most cases. The second test (fitting after the addition of Gaussian noise) revealed the superior performance of the double logistic and Fourier approaches. Finally, when the approaches were applied to the whole study, thus, including vegetation with different phenological profiles and multiple growing seasons (third test), it was found that it was necessary to tune each of the models according to the number of annual growing seasons to produce reliable fits. The double logistic and asymmetric Gaussian models did not perform well for areas with more than one growing season per year. The mean absolute deviation in OG derived from these models was a maximum (3 to 4weeks) within the dry deciduous vegetation type and minimum (1week) in evergreen vegetation. All techniques yielded consistent results over the south-western and north-eastern regions of India characterised by tropical climate.

Analysis of Fault Diagnosis for Rolling Bearing Based on EMD and Local Smoothness Index

A new method based on EMD (empirical mode decomposition) and local smoothness index for rolling bearing fault diagnosis is proposed. With this method, the local smooth index of each IMF (intrinsic mode function) got by empirical mode decomposition is calculated, IMFs with smaller local smoothness index and smaller fluctuation of its smoothness index are selected to analysis with Hilbert envelope spectrum, and the method proposed overcomes blindness of choosing the IMFs with the common EMD envelope method. Factual fault signal of rolling bearing is analyzed; the fault frequency of the rolling bearing is identified accurately

Photon management with core-shell nanowire structures

Antireflective Si/oxide core-shell nanowire arrays (NWAs) were fabricated by galvanic etching and subsequent annealing process. The excellent light-harvesting characteristics of the core-shell NWAs, such as broadband working ranges, omnidirectionality, and polarization-insensitivity, ascribed to the smooth index transition from air to the substrates, have been demonstrated. By tuning core-shell volume ratios, we obtained enhanced light trapping regions implemented in either the planar Si underneath NWAs or the core regions of NWAs, greatly benefiting the geometry design of planar and radial p-n junction cell structures, respectively. This photon management scheme indicates the potential use in nanostructured photovoltaic applications.

A new negative liquid crystal lens with multiple ring electrodes in unequal widths

This study is dedicated to the design of a new negative liquid crystal (LC) lens with multiple ring electrodes in unequal widths. The number and widths of the multiple ring electrodes are designed to offer online tunability on focusing length by predetermined individual electrode voltages. This aims to render a smooth refraction index distribution that mimics well a divergent lens based on the theory of a gradient refraction index (GRIN) lens. Finally, the proposed negative LC lens is fabricated with the capability of realizing different focus lengths in a relatively large aperture of 5 mm and a thickness of 0.7 mm. Experiments are conducted to verify expected light-diverging performance. The effective focus length (EFL) is measured based on interference patterns. It is shown that the proposed negative LC lens is able to realize light-divergent effects with an EFL as short as -357.9 mm.

Solar Cell Architecture: Giant Efficiency Enhancement of GaAs Solar Cells with Graded Antireflection Layers Based on Syringelike ZnO Nanorod Arrays (Adv. Energy Mater. 4/2011)

Architecture innovations are crucial for enhancing the efficiency of solar cells (SCs), which depends on the probability of an incident photon being absorbed. GaAs SCs employing syringe-like ZnO nanorods, providing a smooth index transition from air to the SC surface, show an efficiency boost of 32%. This light-harvesting nanostructure is compatible with existing technology and applicable for various SCs, report Jr-Hau He and co-workers.

Subjects with Metabolic Syndrome Have Higher Chance of Ischemia - Insight from Magnetocardiography

PURPOSE: The purpose of this study was to examine the relationship between endurance capacity, body composition, heart rate and ischemia (measured by magnetocardiography; MCG) in male subjects diagnosed with metabolic syndrome (MS, N=30), as well as age (45∼55yr) matched healthy male subjects (CG, N=35). METHODS: All the subjects were received 6-minute walking, and the % body fat and body mass index (BMI) and MCG measurements. The MCG was analyzed by a receiver operating characteristic curve (ROC Curve). RESULTS: Significantly (p<.05) higher body fat percentage (25.81±4.15 vs. 20.35±5.08 %), fat mass (20.17±4.74 vs. 14.31±4.96 kg), BMI (30.11±4.04 vs. 27.3±2.66 kg/m2) and lower endurance capacity (6-minute walking distance, 642.77±57.04 vs. 732.66±67.49 M) were found in MS group. Resting heart rate and R-R interval were not significantly different between two groups. MCG parameters including the corrected QT interval smooth index (SIQTc) (0.30±0.06 vs. 0.27±0.07), the maximum and minimum QTc interval difference (QTc dispersion) (96.59±14.72 vs. 86.83±15.93), but not the magnetic field gradient orientation (α-Angle), were significantly higher in MS group. Furthermore, QTc dispersion was positively correlated with body fat percentage (R= 0.42) and negatively correlated with endurance capacity (R= -0.31). CONCLUSION: Body fat percentage and endurance capacity are correlated with MCG parameters. The SIQTc and QTc dispersion data suggest that subjects with metabolic syndrome may have a higher chance of ischemia which may be pathologically associated with reduced endurance capacity.

&lt;bold&gt;Optimized synthesis of fiber Bragg gratings with triangular spectrum for wavelength-interrogation application&lt;/bold&gt;

A novel method for synthesizing arbitrary-shape triangular-spectrum fiber Bragg gratings (TS-FBGs) is proposed. It involves the use of a discrete layer peeling method for exploiting initial guess and a simulated annealing method for optimizing the desired grating parameter. By comparing it to the reported TS-FBGs synthesis methods, the proposed method has advantages of reducing the maximum index modulation and smoothing index modulation profile simultaneously. We employ the proposed method to synthesize FBGs with symmetric, asymmetric, and right-angled triangular spectrum, all of which have the low and smooth index modulation profiles. The synthesized gratings can act simple and cost-effective wavelength-interrogation devices in optical sensor systems.

重构多信道光纤光栅的改进离散层析算法

The discrete layer-peeling method for designing multi-channel fiber Bragg grating was optimized.Through the new method,after inserting different phase changes at different channels,the coupling coefficients was then fitted by Gaussian function to get a lower and more smooth refractive index modulation.The simulation results show that a 8-channel fiber Bragg grating is successfully designed using the proposed method with the maximum refractive index modulation of 0.000 5,much lower than that of traditional DLP method(0.001 3),which decreases the requirement of fiber′s optical sensitivity.And,the difficulty of inscribing a fiber grating was reduced by smoothing the refractive index modulation.

Functional Varying Coefficient Models for Longitudinal Data

The proposed functional varying coefficient model provides a versatile and flexible analysis tool for relating longitudinal responses to longitudinal predictors. Specifically, this approach provides a novel representation of varying coefficient functions through suitable auto and cross-covariances of the underlying stochastic processes, which is particularly advantageous for sparse and irregular designs, as often encountered in longitudinal studies. Existing methodology for varying coefficient models is not adapted to such data. The proposed approach extends the customary varying coefficient models to a more general setting, in which not only current but also recent past values of the predictor time course may have an impact on the current value of the response time course. The influence of past predictor values is modeled by a smooth history index function, while the effects on the response are described by smooth varying coefficient functions. The resulting estimators for varying coefficient and history index functions are shown to be asymptotically consistent for sparse designs. In addition, prediction of unobserved response trajectories from sparse measurements on a predictor trajectory is obtained, along with asymptotic pointwise confidence bands. The proposed methods perform well in simulations, especially when compared with commonly used local polynomial smoothing methods for varying coefficient models, and are illustrated with longitudinal primary biliary liver cirrhosis data. The data application and detailed assumptions and proofs can be found in online Supplemental Material.

Changes of protein kinase Cα and cyclin D1 expressions in pulmonary arteries from smokers with and without chronic obstructive pulmonary disease

The purpose of this study was to investigate the changes of protein kinase Calpha (PKCalpha) and cyclin D1 expressions in pulmonary arteries from smokers with normal lung function and smokers with mild to moderate chronic obstructive pulmonary disease (COPD). The peripheral lung tissues were obtained from 10 non-smokers with normal lung function (non-smoker group), 14 smokers with normal lung function (smoker group), 11 smokers with mild to moderate COPD (COPD group). The morphological changes of pulmonary arteries were observed by HE-staining. The expressions of alpha-smooth muscle actin (alpha-SMA), proliferating cell nuclear antigen (PCNA), PKCalpha and cyclin D1 proteins in pulmonary artery smooth muscle cells (PASMCs) were immunohistochemically determined. The percentages of PCNA-positive cells were taken as the smooth muscle cells proliferation index (PI). The mRNA expressions of PKCalpha and cyclin D1 in PASMCs were evaluated by real-time fluorescence PCR. Morphometrical analysis showed that the ratio of pulmonary artery wall area to total area (WA%) in smoker group and COPD group was significantly greater than that in non-smoker group (P<0.01). The PASMCs proliferation index in smoker group and COPD group was significantly higher than that in nonsmoker group (P<0.01). The protein levels of PKCalpha and cyclin D1 in PASMCs were significantly increased in smoker group and COPD group as compared with non-smoker group (P<0.01). The mRNA expressions of PKCalpha and cyclin D1 in PASMCs were significantly elevated in smoker group and COPD group as compared with non-smoker group (P<0.01). Significant correlations were found between PKCalpha protein and WA% or PI (P<0.01). Correlations between cyclin D1 protein and WA% or PI also existed (P<0.01). The expression of PKCalpha was positively correlated with the expression of cyclin D1 at both protein and mRNA levels (P<0.01). In conclusion, increased expressions of PKCalpha and cyclin D1 might be involved in the pathogenesis of abnormal proliferation of PASMCs in smokers with normal lung function and smokers with mild to moderate COPD.

Thick optical waveguides in lithium niobate induced by swift heavy ions (~10 MeV/amu) at ultralow fluences

Heavy mass ions, Kr and Xe, having energies in the approximately 10 MeV/amu range have been used to produce thick planar optical waveguides at the surface of lithium niobate (LiNbO3). The waveguides have a thickness of 40-50 micrometers, depending on ion energy and fluence, smooth profiles and refractive index jumps up to 0.04 (lambda = 633 nm). They propagate ordinary and extraordinary modes with low losses keeping a high nonlinear optical response (SHG) that makes them useful for many applications. Complementary RBS/C data provide consistent values for the partial amorphization and refractive index change at the surface. The proposed method is based on ion-induced damage caused by electronic excitation and essentially differs from the usual implantation technique using light ions (H and He) of MeV energies. It implies the generation of a buried low-index layer (acting as optical barrier), made up of amorphous nanotracks embedded into the crystalline lithium niobate crystal. An effective dielectric medium approach is developed to describe the index profiles of the waveguides. This first test demonstration could be extended to other crystalline materials and could be of great usefulness for mid-infrared applications.

Saccadic and smooth pursuit eye movements in memory-impaired elderly people.

The aim of the study was to compare eye movements recorded in 14 non-demented memory impaired elderly subjects with those of 36 sex- and education-matched controls. Eye movements were recorded with the bitemporal electrooculographic technique, and analyzed with a personal computer. Saccades were elicited in accordance with reflexive, predictive and antisaccade paradigms. Smooth pursuit eye movements were elicited with a triangular ramp paradigm. The memory-impaired subjects showed a higher prevalence of increased reflexive saccade latency and a lower smooth pursuit performance index. In addition, we detected a correlation between antisaccade and reflexive saccade latencies. Our results showed very slight differences in eye movement parameters. However, our findings are in keeping with the hypothesis of a subtle involvement of differing cortical areas in memory impaired subjects.

Higher Torsion Invariants in Differential Topology and Algebraic K-Theory

The classical Franz–Reidemeister torsion and its cousins, the Whitehead torsion and Ray–Singer analytic torsion, are topological invariants of manifolds with local coefficient systems (or flat vector bundles) that can distinguish homotopy equivalent spaces that are not homeomorphic. The purpose of this Arbeitsgemeinschaft was to learn about several natural generalisations of these classical invariants to families of manifolds. Regard a family p\colon E\to B of compact manifolds M , equipped with a flat vector bundle F\to M . Then the fibrewise cohomology groups H^\bullet(E/B;F) form flat vector bundles over the base B . The starting point for our investigations are analogues of the Atiyah–Singer family index theorem that relate F to H^\bullet(E/B;F) . To a flat vector bundle F\to M , one associates Kamber–Tondeur characteristic classes c_\bullet(F) in H^{\text{odd}}(M;\mathbb R) , which vanish if F carries a parallel metric. By Bismut–Lott [1], one has \sum_i(-1)^ic_\bullet\bigl(H^i(E/B;F)\bigr) =\int_{E/B}e(TM)\,c_\bullet(F) \quad\in H^*(B;\mathbb R)\;, where e(TM) is the Euler class of the vertical tangent bundle, and the right hand side is the Becker–Gottlieb transfer in de Rham cohomology. If one specifies some additional geometric data, then all classes above are naturally represented by specific differential forms. On the level of differential forms, the equation above only holds up a correction term d\mathcal T . Here \mathcal T is the higher analytic torsion, which depends naturally on the fibration and the geometric data. If both H^\bullet(E/B;F) and F admit parallel metrics, then \mathcal T gives rise to a secondary characteristic class \mathcal T(E/B;F)\in H^{\text{even},\ge2}(B;\mathbb R) . Dwyer–Weiss–Williams [2] construct Reidemeister torsion for a smooth fiber bundle p\colon E \to B as a byproduct of a family index theory. If p is any fiber bundle with fibers compact topological manifolds and base a CW complex, then the family index theory states that \chi(p) , the A-theory Euler characteristic of p is determined by the A-theory Euler class of \tau_{fib}(p), the tangent bundle along the fiber. Here A-theory is algebraic K-theory of spaces in the sense of Waldhausen. More precisely, by applying fiberwise Poincare duality, and then an assembly map to the A-theory Euler class, one gets the A-theory Euler characteristic. If p is a smooth bundle, then one gets a stronger smooth index theorem where the A-theory Euler class is replaced by the Becker–Euler class, which lives in the (twisted) stable cohomotopy of E . When B is a point this result is equivalent to the classical Poincare–Hopf theorem. The third approach is due to Igusa–Klein [3], and is somewhat different in nature. Here, one regards a generalised fibrewise Morse function on M\to B . Together with a flat vector bundle F\to M , this gives rise to a classifying map from B to a Whitehead space, and the higher Franz–Reidemeister torsion is the pullback of a universal class on the Whitehead space. There are conjectural relations between all three definitions of higher torsion. In a special case, Igusa has characterized higher Franz–Reidemeister torsion axiomatically; checking these axioms for either of the other higher torsions would prove equality. For some bundles, equality of higher Franz–Reidemeister torsion and higher analytic torsion can be shown analytically using the Witten deformation. Finally, one expects that higher Franz–Reidemeister torsion can be recovered from Dwyer–Weiss–Williams torsion. It turns out that higher torsion invariants are somewhat finer than classical FR torsion, since they detect higher homotopy classes of the diffeomorphism group of high-dimensional manifolds that vanish under the forgetful map to the homeomorphism group. In particular, these invariants distinguish differentiable structures on a given topological fibre bundle M\to B , where one may even fix differentiable structures on M , B and the typical fibre. There are also applications of higher torsions to problems in graph theory and moduli spaces of compact surfaces. Some of these were sketched throughout this Arbeitsgemeinschaft. The talks were grouped as follows. The meeting took place from April 2nd till April 8th 2006 and was organized by Sebastian Goette (Regensburg), Kiyoshi Igusa (Brandeis) and Bruce Williams (Notre Dame). It was attended by 43 participants, coming mainly from Europa and the USA.

Liquid-crystal panel with microdots on an electrode used to modulate optical phase profiles

The optical characteristics of a liquid-crystal (LC) panel with microdots on an electrode are investigated. Although 3 mum is larger than 1 molecule of LC material, microdots with a 3 microm diameter are sufficiently small to produce a smooth index profile. We use an electrode patterned in a new way to modulate the index profile of the LC panel, which allows us to modulate the optical phase of the passing light.

Index profiling of anisotropic graded-index planar waveguides from effective indices

We present a method for recovering the refractive-index profile of an anisotropic graded-index waveguide from the effective indices by using a cubic spline interpolation function. The first and second derivatives of cubic splines are continuous to ensure a smooth index profile, which is consistent with practical graded-index distributions. A straightforward iteration with an exact dispersion equation to verify the interpolated profile makes this method easy and reliable for application. This approach is proved by numerical analysis of several typical index distributions and experimental examples showing that the refractive-index profiles in anisotropy can be reconstructed close to the exact profile. Waveguides with both more modes (more than four guiding modes) and fewer modes (two to four) can be universally profiled with good accuracy.

SPACES OF LIPSCHITZ TYPE ON METRIC SPACES AND THEIR APPLICATIONS

AbstractNew spaces of Lipschitz type on metric-measure spaces are introduced and they are shown to be just the well-known Besov spaces or Triebel–Lizorkin spaces when the smooth index is less than 1. These theorems also hold in the setting of spaces of homogeneous type, which include Euclidean spaces, Riemannian manifolds and some self-similar fractals. Moreover, the relationships amongst these Lipschitz-type spaces, Hajłasz–Sobolev spaces, Korevaar–Schoen–Sobolev spaces, Newtonian Sobolev space and Cheeger–Sobolev spaces on metric-measure spaces are clarified, showing that they are the same space with equivalence of norms. Furthermore, a Sobolev embedding theorem, namely that the Lipschitz-type spaces with large orders of smoothness can be embedded in Lipschitz spaces, is proved. For metric-measure spaces with heat kernels, a Hardy–Littlewood–Sobolev theorem is establish, and hence it is proved that Lipschitz-type spaces with small orders of smoothness can be embedded in Lebesgue spaces.AMS 2000 Mathematics subject classification: Primary 42B35. Secondary 46E35; 58J35; 43A99

Creating Effective Refractive Index Gradients within Polyelectrolyte Multilayer Films: Molecularly Assembled Rugate Filters

We demonstrate the use of aqueous-based layer-by-layer (LbL) processing and in situ nanoreactor chemistry for creating polyelectrolyte multilayer (PEM) nanocomposites in which the concentration of a nanoparticle species is modulated throughout the depth of the film in a complex way. Using the in situ growth of silver nanoparticles to selectively increase the refractive index of precisely defined regions of the PEM film, we have produced a digitized rugate filter, a special type of dielectric mirror possessing many thin layers that approximate a continuous, periodic refractive index profile. The design of the digital rugate from an initial smooth index profile was aided by a computer, and construction of the device was accomplished entirely by automated means. Poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) bilayer regions within the film supported subsequent nanoreactor chemistry and created the high refractive index regions of the film, while PAH and poly(styrenesulfonate) (PSS) bilayer regions remained unmodified and served as the low index regions. Spectroscopic results obtained from the assembled device confirm the presence of a reflection band that grows in amplitude with increasing silver incorporation, reaching a peak reflectance of 75% after five silver loading and exchange cycles. The rugate structure suppresses reflection sidebands, features common to Bragg reflectors and simpler dielectric mirror designs. Cross-sectional TEM reveals nanoscale control of the size and location of silver-containing domains within the PEM film. The ability of this method to control the placement of nanoparticles within PEMs enables the inexpensive, easy production of conformable optical coatings with tunable properties. In addition, these nanocomposite films may have applications in a number of other fields where precise control of effective gradients in physical properties throughout thin films has been shown to affect the overall performance in a desirable way.

813-4 Smooth muscle cell proliferation index correlates with indium-111 Z2D3 antibody uptake in a transplant vasculopathy swine model

813-4 Smooth muscle cell proliferation index correlates with indium-111 Z2D3 antibody uptake in a transplant vasculopathy swine model

Regulation of rat prostate stromal cell myodifferentiation by androgen and TGF-beta1.

Myodifferentiation of stromal cells is a key step in prostate development and is a hallmark of reactive stroma in prostate cancer. Little is known about regulatory mechanisms, however, prostate stromal cells are androgen-regulated and TGF-beta1 is a known stimulator of stromal myodifferentiation. The PS-1 rat prostate stromal cell line expresses androgen receptor, and exhibits androgen-regulated gene expression and proliferation. TGF-beta1 inhibits androgen action in PS-1 cells through translocation of androgen receptor from the nucleus to the cytoplasm. The present study was conducted to determine whether myodifferentiation of PS-1 cells is regulated by androgen and TGF-beta1, and how myodifferentiation affects androgen receptor localization and cell proliferation. PS-1 cell cultures were exposed to physiological concentrations of dihydrotestosterone, TGF-beta1, and combinations of both in chemically defined medium. Immunocytochemistry and Western blotting for smooth muscle alpha-actin filament formation, smooth muscle alpha-actin protein levels, calponin expression, PCNA index, and androgen receptor localization were performed. Dihydrotestosterone (DHT) and TGF-beta1 each separately promoted PS-1 myodifferentiation. A combination did not affect the rate of differentiation, however, the level of alpha-actin protein was elevated and PCNA was decreased in co-stimulated conditions. TGF-beta1 induction resulted in a transient translocation of androgen receptor from the nucleus to the cytoplasm during differentiation followed by a resumed nuclear localization in myodifferentiated cells. These data indicate that a complex cross-talk mechanism exists between androgen and TGF-beta1 signaling in prostate stromal cells that affects cell proliferation and myodifferentiation. These findings also suggest that androgen and TGF-beta1 interactions may cooperatively regulate myodifferentiation of stromal cells in the stromal response in prostate cancer.

Uniform attractors of nonautonomous index 2 differential algebraic equations under discretization

The long‐time behaviour of Runge–Kunge discretizations is investigated when applied to a smooth nonautonomous index 2 differential algebraic equation (DAE) with a cocycle structure, i.e. a DAE driven by an autonomous dynamical system, which is assumed to have a uniform attractor. It is shown that the cocycle structure of the continuous dynamics is preserved under discretization and that a uniform forward or pullback attractor of the DAE persists under discretization by a Runge–Kutta scheme with the component subsets of the numerical attractor converging upper semicontinuously to their continuous time counterparts.