Miracle-dz/UniFAR-FTUs huggingface dataset:
A note on calculating the slice genus of 11- and 12-crossing knots

This short note contains the results of efforts to determine values of the smooth slice genus for 11- and 12-crossing knots. Primarily, we used a computer to search for genus one concordances between knots. Further results were obtained using an obstruction arising from Donaldson's diagonalization theorem. This also allows us to deduce the topological slice genus for many knots.
Adiabatic bond charge model for the phonons in diamond, Si, Ge, and α-Sn

An adiabatic bond charge model (BCM) for the lattice dynamics of diamond-type crystals is developed. Our BCM unites elements of earlier models by Phillips and Martin, Keating, and Cochran. Four types of interactions are used: (a) central ion-ion forces, (b) Coulomb interactions of the ions and bond charges (BC's), (c) central ion-BC forces, and (d) bond-bending forces. These interactions represent the metal-like (a) and covalent (b)-(d) part of the crystal bonding. The phonon dispersion curves for Si, Ge, and $\ensuremath{\alpha}\ensuremath{-}\mathrm{Sn}$ are calculated using only four disposable parameters; for diamond, five parameters are employed. For all crystals, very good agreement with experiment is obtained. In particular, the typical flattening of the transverse acoustic phonons in the semiconducting materials is understood as a consequence of the adiabatic motion of the BC's, when the effective ion-BC coupling (b)+(c) is weak compared to the bond-bending forces (d). In an alternative representation of the BCM, the interactions (b) and (c) are replaced by central and noncentral ion-BC-ion potentials along one bond. The remaining long-range part of the Coulomb forces is unimportant; therefore, all essential interactions of the BCM are of very short range. Furthermore, the interaction parameters follow clear trends from diamond to $\ensuremath{\alpha}\ensuremath{-}\mathrm{Sn}$: type (a) increases, whereas types (b)-(d) decrease, especially the ion-BC coupling tends to vanish toward $\ensuremath{\alpha}\ensuremath{-}\mathrm{Sn}$.
On numerical solution of third‐order boundary‐value problems

A fourth-order method is developed for the approximation of the solution of certain two-point boundary-value problems involving third-order linear and non-linear differential equations. The method arises from a four-point recurrence relation involving exponential terms, these being replaced by Pade approximants. The convergence of the method is discussed. The method is tested on two problems to demonstrate the practical usefulness of the approach.
Shocks in the evolution of an eroding channel

Author(s): Welsh, Edward; Birnir, Bjorn; Bertozzi, Andrea L. | Abstract: Analysis of an evolution model for a river channel shows how three types of shocks determine the profile of the channel. This model shows that in a young river channel, evolution is driven by white noise magnifying into a bore followed by a hydraulic jump. This mechanism produces a convex profile typical of young landscapes. A small knick-point then develops at the bottom of the unstable convex profile. This knick-point is magnified and colored into a diffusive shock which travels upslope, digging into the convex profile until the profile becomes concave, typical of mature landscapes.
Verification of Threshold Voltage Variation of Scaled Transistors with Ultralarge-Scale Device Matrix Array Test Element Group

Randomness of threshold voltage (VT) variations of negative channel field effect transistors (NFETs) and positive channel field effect transistors (PFETs) in the 65 nm technology is precisely examined. For this purpose, an ultralarge-scale device matrix array test element group (DMA-TEG) that contains 1 million single-size metal–oxide–semiconductor field-effect transistors (MOSFETs) has been designed and fabricated, and a very rapid measurement system has been developed. By evaluating VT of a very large number of MOSFETs, VT variation can be precisely evaluated. This rapid measurement is achieved by parallel address signal input, optimization of the measurement program, and 4-chip parallel measurements. The measured VT variations are decomposed into random and systematic components. The results reveal that the random component is overwhelmingly dominant in the VT variations in the 65 nm technology and that the VT variations exhibit a normal distribution up to ±5σ.
Simulated Turbulent Flow and Forces Around Groups of Cylinders

Results from numerical simulations of flow at high Reynolds numbers around cylinders and associated forces are presented. The numerical model is based on the discrete vortex model combined with an integrated boundary layer model. Hereby it has become possible to include the influence of the pope roughness on the flow and the associated forces. The paper summarises the theoretical basis for the model, including the boundary layer part and a simple approach for including the diffusion of rotation. Results obtained from the simulations with arrays of 2, 4 and 8 cylinders are presented. Steady flow and oscillatory flow cases are covered.
On the distributed Lagrange multiplier/fictitious domain method for rigid‐particle‐laden flows: a proposition for an alternative formulation of the Lagrange multipliers

The distributed Lagrange multiplier/fictitious domain method proposed for the direct numerical simulation of particle‐laden flows is considered in this work. First, it is demonstrated that improved accuracy is obtained with a coupled numerical scheme, whereby the pressure and the Lagrange multiplier fields enforcing incompressibility and rigid body motion, respectively, are calculated and applied together. However, the convergence characteristics of the iterative solution of the coupled scheme are poor because symmetric but indefinite and poorly conditioned matrices are produced. An analysis is then presented, which suggests that the cause for the matrix pathologies lies in the interaction of the respective matrix operators enforcing incompressibility and rigid body motion. On the basis of this analysis, an alternative formulation is developed for the Lagrange multipliers, being now composed of a set of forces distributed only on the particle boundary together with a set of couples distributed within the particle core. The new formulation is tested with several types of flows with stationary or moving particles under creeping or finite Reynolds number conditions and it is demonstrated that it produces correct results and better conditioned matrices, thus enabling faster and more reliable convergence of the conjugate gradient method. The analysis and tests, therefore, support the expectation that the proposed formulation is promising and worthy of further study and improvement. Copyright © 2011 John Wiley & Sons, Ltd.
Ocean State Forecast along Ship Routes: Evaluation Using ESSO-INCOIS Real-Time Ship-Mounted Wave Height Meter and Satellite Observations*

AbstractOcean state forecast (OSF) along ship routes (OAS) is an advisory service of the Indian National Centre for Ocean Information Services (INCOIS) of the Earth System Science Organization (ESSO) that helps mariners to ensure safe navigation in the Indian Ocean in all seasons as well as in extreme conditions. As there are many users who solely depend on this service for their decision making, it is very important to ensure the reliability and accuracy of the service using the available in situ and satellite observations. This study evaluates the significant wave height (Hs) along the ship track in the Indian Ocean using the ship-mounted wave height meter (SWHM) on board the Oceanographic Research Vessel Sagar Nidhi, and the Cryosat-2 and Jason altimeters. Reliability of the SWHM is confirmed by comparing with collocated buoy and altimeter observations. The comparison along the ship routes using the SWHM shows very good agreement (correlation coefficient > 0.80) in all three oceanic regimes, [the tropi.
VLBI observations of the 6.7 GHz methanol masers toward W3(OH)

We have conducted very long baseline interferometric (VLBI) observations of the 6.668 GHz maser transition of interstellar methanol toward the ultracompact H II region W3(OH). We have determined absolute maser positions with an accuracy of 0″. 05 and produced maps that show that the methanol masers have a distribution similar to the hydroxyl masers in this source. The intrinsic sizes of individual maser spots are ≃0″. 0014 (FWHM), or ≃3 AU, and are not significantly affected by interstellar scattering
Possible Breakdown of the Alexander-Orbach Rule at Low Dimensionalities

Simple conditions are presented under which the fractal dimension of a random walk on an aggregate, ${d}_{w}$, is given by ${d}_{w}=D+1$, where $D$ is the aggregate's fractal dimension. These conditions are argued (with one simple speculative assumption) to apply for $Dl2$, implying a breakdown of the Alexander-Orbach rule ${d}_{w}=\frac{3D}{2}$. Existing results for percolation clusters, lattice animals, and diffusion-limited aggregates seem to favor our new rule.
Identification for long-range predictive control

The current generation of adaptive predictive controllers uses a standard single-step-ahead estimator with multi-step-ahead predictors. In order to obtain satisfactory results in applications, data are bandpass filtered before being used in the estimator. This paper demonstrates that the use of a standard RLS estimator with no data filtering frequently results in unstable closed loops if the parameters are used in a multi-step-ahead control scheme. A multi-step-ahead cost is introduced for parameter estimation as a dual of the control law. It is shown that the method is superior to the standard scheme. The frequency response properties of this estimator indicate that prefiltering of the data prevalent among the reported successful applications of the predictive controller is a natural outcome of this choice of the cost for the estimator scheme. The paper provides some useful guidelines for the choice of order and time constants of these filters.
On modeling of discrete propagation of localized damage in cohesive‐frictional materials

In this paper, the problem of propagation of localized deformation associated with formation of macrocracks/shear bands is studied in both tensile and compressive regimes. The main focus here is on enhancement of the constitutive law with embedded discontinuity to provide a discrete representation of the localization phenomenon. This has been accomplished by revising the formulation and coupling it with the level‐set method for tracing the propagation path. Extensive numerical studies are conducted involving various fracture modes, ranging from brittle to frictional, and the results are compared with the experimental data as well as those obtained using XFEM methodology. Copyright © 2015 John Wiley & Sons, Ltd.
Ground radiation scattered from feed support struts: A significant source of noise in paraboloidal antennas

The struts supporting the feed or subreflector of a symmetrical paraboloidal antenna generate sidelobes around cones of wide opening angle by scattering energy from the plane wave leaving the reflector. On the basis of simple assumptions about these “scatter cone” sidelobes, an approximate formula is derived to predict their level relative to the main beam; it is tested against published measurements. The noise added to the antenna when the scatter cone sidelobes receive radiation from the ground is calculated, and this mechanism is seen as a significant contributor to antenna noise. The use of struts of triangular cross section in place of circular ones redirects sidelobe energy away from the back hemisphere of the radiation pattern to the front hemisphere. For most antenna pointings these sidelobes will not strike the ground, and antenna noise temperature is likely to be reduced. Radiometric measurements at 1420 MHz have been made using a 9-m antenna equipped with struts of various cross sections and sizes. These measurements have been used to isolate the strut contribution to antenna noise, and have verified that this contribution can be reduced by using triangular struts. The strut contribution to antenna noise is calculated as a function of zenith angle of the main beam of the antenna. Triangular struts are superior to circular ones at all main-beam zenith angles. When three struts are used, the upright Y configuration of the tripod is better than the inverted Y.
Reflection of a planar ion‐acoustic soliton from a finite plane boundary

Experimental observations on the partial reflection of a planar ion‐acoustic soliton from a plane rigid boundary with sharp density gradients are presented. The reflected wave attenuates rapidly, forming a spherical wave front apart from a small reflector. The reflection coefficient of about 25% at the boundary has no apparent dependence on the incident wave amplitude and the sheath thickness in front of the reflector in the case of the disk reflector, while it has a dependence in the case of the mesh reflector, having even larger values of up to about 50%.
Sensitive mapping of E and S0 galaxies in search of H I content differences between supernovae and non-supernovae producing galaxies

Thirteen elliptical and S0 galaxies in the Virgo and Pegasus I clusters have been mapped over their optical extent in the 21-cm neutral hydrogen line with the 305-m Arecibo telescope. No neutral hydrogen was detected in any of the galaxies, including NGC 4636, which had previously been reported as containing H I. New upper limits to the H I content of these galaxies (approx.5 x 10/sup 7/M/sub sun/ in Virgo) are presented. We discuss their implications for the origin of type I supernovae and the mechanisms for gas removal from elliptical galaxies.
Cumulonimbus Vertical Velocity Events in GATE. Part II: Synthesis and Model Core Structure

Abstract The properties of convective drafts and cores are presented in Part I. By our definition a convective updraft must have a positive vertical velocity for 0.5 km, and exceed 0.5 m s−1 for 1 s; a convective updraft core must exceed 1 m s−1 for 0.5 km. Downdrafts and downdraft cores are defined analogously. Here the properties of the drafts and cores are compared to results of previous work. In addition, the implications of the results in Part I are discussed. GATE cores and drafts are comparable in size and intensity to those measured in hurricanes but weaker than those measured in continental thunderstorms. The lesser intensity seems related to the nearly moist adiabatic GATE sounding. The mass flux by GATE cores is consistent with large-scale requirements. It is fairly evenly distributed over a range of core size and intensity. Updraft core vertical velocity and diameter are positively correlated, primarily the result of a few large strong events. The vast majority of GATE convective cores are suf.
Reducing Climatology Bias in an Ocean-Atmosphere CGCM with Improved Coupling Physics.

Abstract The cold tongue in the tropical Pacific extends too far west in most current ocean–atmosphere coupled GCMs (CGCMs). This bias also exists in the relatively high-resolution SINTEX-F CGCM despite its remarkable performance of simulating ENSO variations. In terms of the importance of air–sea interactions to the climatology formation in the tropical Pacific, several sensitivity experiments with improved coupling physics have been performed in order to reduce the cold-tongue bias in CGCMs. By allowing for momentum transfer of the ocean surface current to the atmosphere [full coupled simulation (FCPL)] or merely reducing the wind stress by taking the surface current into account in the bulk formula [semicoupled simulation (semi-CPL)], the warm-pool/cold-tongue structure in the equatorial Pacific is simulated better than that of the control simulation (CTL) in which the movement of the ocean surface is ignored for wind stress calculation. The reduced surface zonal current and vertical entrainment owing .
Comparison of three methods for the measurement of printed antenna efficiency

Three methods for the measurement of antenna efficiency are evaluated: (1) the Wheeler cap method, (2) the radiometric method, and (3) the directivity/gain method. Each of these methods was used to measure the efficiency of four different printed antennas (three microstrip patches with various feeds, and an eight-element series-fed microstrip array). These methods and the experimental results which were obtained are discussed. >
Implications of emission zone limits for the Ruderman-Sutherland pulsar model

In the Ruderman-Sutherland (RS) pulsar model the frequency at which coherent radiation is emitted depends upon the source location, v=v (r). In the oblique rotator version of this model the time-averaged tangential velocities of the magnetosphere sources must increase linearly with radius, and this leads to a frequency-dependent aberration and retardation time delay in which higher frequencies lag behind lower frequencies. As previously noted by Cordes, within the context of a given model which specifies v (r), the absence of any anomalous time delay in dispersion measurements allows limits to be placed on the radial position of the source of a given frequency. In this paper we (a) give a time-delay analysis (similar to that of Cordes) appropriate for the RS model and show that existing dispersion measurements are incompatible with RS emission mechanism. If the basic RS emission mechanism is applicable to pulsars, we find that the most plausible modification consistent with the dispersion data is a reduction in the low-energy plasma density by a factor approx.10/sup -4/ to 10/sup -5/. This has the effect of bringing the radio emission zone closer to the stellar surface, thereby making the model consistent with the dispersion data. In addition, this modificationmore » results in a significant decrease in the predicted maximum cone angle and an increase in the predicted maximum frequency by factors which bring these predictions more in line with observation. We also consider implications of a reduced plasma density for radio luminosity. « less
Lasso penalized semiparametric regression on high-dimensional recurrent event data via coordinate descent

This paper studies a fast computational algorithm for variable selection on high-dimensional recurrent event data. Based on the lasso penalized partial likelihood function for the response process of recurrent event data, a coordinate descent algorithm is used to accelerate the estimation of regression coefficients. This algorithm is capable of selecting important predictors for underdetermined problems where the number of predictors far exceeds the number of cases. The selection strength is controlled by a tuning constant that is determined by a generalized cross-validation method. Our numerical experiments on simulated and real data demonstrate the good performance of penalized regression in model building for recurrent event data in high-dimensional settings.
An Experimental Study of Cracking Induced by Desiccation

Experiments on cracking in drying a coffee-water mixture were carried out, in order to model mud cracks occurring in nature. The results show that the main source of stresses required for cracking is the friction at the bottom of the container, in which the mixture is kept. There is a linear relation between the scale of the crack pattern and the thickness of the mixture layer. Statistics of the angles between joining cracks is presented. A general mechanism of mud cracks formation is proposed.
Label-free SHG imaging and spectral FLIM of corneas using a sub-15 fs laser microscope

Alterations to the corneal cell metabolism or to the structural organization of collagen fibrils occur in several corneal and systemic pathologies. In this work we resort to multiphoton microscopy corneal imaging to achieve a characterization of the corneal state. Using fluorescence lifetime imaging microscopy (FLIM) the assessment of the metabolic state of corneal cells is possible, whereas second harmonic generation (SHG) imaging can be used to assess corneal structural alterations. A sub-15 fs near-infrared laser source with a broad excitation spectrum was used for SHG imaging and FLIM. The broad spectrum allows simultaneous excitation of both metabolic co-factors. The signals were collected by a photomultiplier tubes (PMT) detector with 16 simultaneous recording channels, which allowed the separation of fluorophores autofluorescence based on their emission wavelengths. We were able to successfully image ex-vivo human and porcine cornea at multiple depths. Simultaneous NADH and flavin autofluorescence, SHG of collagen fibrils, and stroma autofluorescence imaging was performed which may in future allow an improved characterization of the metabolic and structural alterations of the corneal tissue due to pathophysiological conditions. This would be an important step towards a better understanding of corneal dystrophies and systemic metabolic disorders.
Do firms learn by exporting or learn to export? Evidence from Senegalese manufacturing plant

This paper examines the causal relationship between exporting and productivity in the manufacturing firms in Senegal using a unique firm-level panel data for the period 1998-2011. We control for endogeneity and sample selection by jointly estimating the productivity and the export-participation equations. Our results indicate strong evidence of both self-selection of the most efficient firms enter into the export market and effect of Learning in the export market. Findings show that firms with better financial health are likely to exports. Furthermore, the ownership of intangible assets like brevet and the quality of labour positively affect the probability to export of the manufacturing firms. We investigate the sectoral heterogeneity of the Learning-by exporting effect (LBE) and find evidence of a weak heterogeneity of the learning-by-exporting effect between the sectors. From a policy relevance, the evidence of learning-by-exporting suggests Senegal has much to gain from encouraging exports by helping domestic firms to overcome the barriers to enter into foreign markets by promoting access to intangible assets like brevet Particularly, export promotion policies could be helpful, reducing the level of financial constraints faced by firms, and indirectly enhancing their investment spending and productivity. As a driver of manufacturing exports, labour quality must be carefully considered in the perspectives of industrial development. Considerable efforts are required in the Senegalese educational system in order to match the training to the requirements of the labour market.
Quantum coding theorems

Contents I. Introduction II. General considerations § 1. Quantum communication channel § 2. Entropy bound and channel capacity § 3. Formulation of the quantum coding theorem. Weak conversion III. Proof of the direct statement of the coding theorem § 1. Channels with pure signal states § 2. Reliability function § 3. Quantum binary channel § 4. Case of arbitrary states with bounded entropy IV. c-q channels with input constraints § 1. Coding theorem § 2. Gauss channel with one degree of freedom § 3. Classical signal on quantum background noise Bibliography