Lyapunov functionals for boundary-driven nonlinear drift-diffusions

We exhibit a large class of Lyapunov functionals for nonlinear drift-diffusion equations with non-homogeneous Dirichlet boundary conditions. These are generalizations of large deviation functionals for underlying stochastic many-particle systems, the zero range process and the Ginzburg-Landau dynamics, which we describe briefly. As an application, we prove linear inequalities between such an entropy-like functional and its entropy production functional for the boundary-driven porous medium equation in a bounded domain with positive Dirichlet conditions: this implies exponential rates of relaxation related to the first Dirichlet eigenvalue of the domain. We also derive Lyapunov functions for systems of nonlinear diffusion equations, and for nonlinear Markov processes with non-reversible stationary measures

High density Schottky barrier IRCCD sensors for SWIR applications at intermediate temperature

Monolithic 32 x 64 and 64 x 1:128 palladium silicide (Pd2Si) interline transfer infrared charge coupled devices (IRCCDs) sensitive in the 1 to 3.5 micron spectral band were developed. This silicon imager exhibits a low response nonuniformity of typically 0.2 to 1.6% rms, and was operated in the temperature range between 40 to 140 K. Spectral response measurements of test Pd2Si p-type Si devices yield quantum efficiencies of 7.9% at 1.25 microns, 5.6% at 1.65 microns 2.2% at 2.22 microns. Improvement in quantum efficiency is expected by optimizing the different structural parameters of the Pd2Si detectors. The spectral response of the Pd2Si detectors fit a modified Fowler emission model. The measured photo-electric barrier height for the Pd2Si detectors is 0.34 eV and the measured quantum efficiency coefficient, C1, is 19%/eV. The dark current level of Pd2Si Schottky barrier focal plane arrays (FPAs) is sufficiently low to enable operation at intermediate temperatures at TV frame rates. Typical dark current level measured at 120 K on the FPA is 2 nA/sq cm. The operating temperature of the Pd2Si FPA is compatible with passive cooler performance. In addition, high density Pd2Si Schottky barrier FPAs are manufactured with high yield and therefore represent an economical approach to short wavelength IR imaging. A Pd2Si Schottky barrier image sensor for push-broom multispectral imaging in the 1.25, 1.65, and 2.22 micron bands is being studied. The sensor will have two line arrays (dual band capability) of 512 detectors each, with 30 micron center-to-center detector spacing. The device will be suitable for chip-to-chip abutment, thus providing the capability to produce large, multiple chip focal planes with contiguous, in-line sensors

On the uniqueness for the spatially homogeneous Boltzmann equation with a strong angular singularity

We prove an inequality on the Wasserstein distance with quadratic cost between two solutions of the spatially homogeneous Boltzmann equation without angular cutoff, from which we deduce some uniqueness results. In particular, we obtain a local (in time) well-posedness result in the case of (possibly very) soft potentials. A global well-posedeness result is shown for all regularized hard and soft potentials without angular cutoff. Our uniqueness result seems to be the first one applying to a strong angular singularity, except in the special case of Maxwell molecules. Our proof relies on the ideas of Tanaka: we give a probabilistic interpretation of the Boltzmann equation in terms of a stochastic process. Then we show how to couple two such processes started with two different initial conditions, in such a way that they almost surely remain close to each other

Association between spondylolisthesis and L5 fracture in patients with osteogenesis imperfecta

To investigate if an association between spondylolisthesis and L5 fracture occurs in patients affected by Osteogenesis Imperfecta (O.I.). Methods Anteroposterior and lateral radiograms were performed on the sample (38 O.I. patients, of whom 19 presenting listhesis); on imaging studies spondylolisthesis was quantified according to the Meyerding classification. Genant’s semiquantitative classification was applied on lateral view to evaluate the L5 fractures; skeleton spinal morphometry (MXA) was carried out on the same images to collect quantitative data comparable and superimposable to Genant’s classification. The gathered information were analyzed through statistical tests (O.R., χ 2 test, Fisher’s test, Pearson’s correlation coefficient). Results The prevalence of L5 fractures is 73.7 % in O.I. patients with spondylolisthesis and their risk of experiencing such a fracture is twice than O.I. patients without listhesis (OR 2.04). Pearson’s χ 2 test demonstrates an association between L5 spondylolisthesis and L5 fracture, especially with moderate, posterior fractures (p = 0.017) and primarily in patients affected by type IV O.I. Conclusions Spondylolisthesis represents a risk factor for the development of more severe and biconcave/posterior type fractures of L5 in patients suffering from O.I., especially in type IV. This fits the hypothesis that the anterior sliding of the soma of L5 alters the dynamics of action of the load forces, localizing them on the central and posterior heights that become the focus of the stress due to movement of flexion–extension and twisting of the spine. As a result, there is greater probability of developing an important subsidence of the central and posterior walls of the soma

Estimation of Local Mean Population Densities of Japanese Beetle Grubs (Scarabaeidae: Coleoptera)

Insect populations tend to be patchy in distribution. Even when the mean population density is low, there may be local patches with high densities. As a result, estimates of mean populations may provide little information about the size or intensity of local patches within the sampled area. We compared the following 3 methods of estimating local population densities of insects: (1) with moving averages, a local mean population density is estimated as the mean of samples taken within a given radius of a central point, (2) with inverse distances, local means are estimated as weighted averages of samples; each sample is given a weight proportional to a power of the reciprocal of its distance from the center of the region for which the mean is to be estimated, (3) kriging is a geostatistical algorithm for estimating local means as weighted averages of samples. Weighting is based on the spatial covariance of the samples, or the degree to which samples that are near to each other are related. The first 2 methods are relatively easy to calculate but were unreliable when used with standard parameters to estimate local Japanese beetle grub densities. When an optimum radius was used with moving averages and an optimum exponent was used with inverse distances, the advantage of ease of calculation was lost, yet both methods were still inferior to kriging in providing accurate estimates of local mean

Age-Dependent Movement Patterns of Japanese Beetle and European Chafer (Coleoptera: Scarabeidae) Grubs in Soil-Turfgrass Microcosms

Movement patterns of japanese beetle, Popillia japonica Newman, and European chafer, Rhizotrogus (Amphimallon) majalis (Razoumowsky), grubs as influenced by gravity, host plant position, and external disturbances were studied in laboratory soil-turfgrass microcosms. Second through third instars just before pupation were monitored using radiographic techniques. Neonates were monitored using destructive sampling. Results demonstrate significantly different movement patterns between species and among age groups. The development stage of the grub had a large effect on Japanese beetle grub behavior and a measurable, but lesser effect, on European chafers. All larval stages of European chafers and all larval stages of Japanese beetle, except neonates and postoverwintering third instars, displayed a downward movement in response to disturbance. Neonate Japanese beetles showed little movement while postoverwintering. Japanese beetles moved upward when disturbed. European chafer grubs of all age classes displayed random vertical movement with some arrestment in or near sod. Preoverwintering and postoverwintering third-instar chafers showed less dramatic arrestment behavior than other instars tested. Second-instar Japanese beetles behaved similarly to European chafers; however, third instars behaved very differently. All third instars except those tested in late winter and early spring showed some innate downward movement in the soil microcosms. Japanese beetles tested in late winter displayed random movement with some arrestment in sod, whereas those tested in early spring exhibited upward movement and arrestment in so

Environmental Influences on Soil Macroarthropod Behavior in Agricultural Systems

Many basic and applied studies in insect ecology have focused on the proximate and ultimate responses of insect populations to their physical and chemical environment (2, 15, 21, 27, 32, 74, 82, 111, 112). From an economic perspective, macro- and microclimatic factors can influence the stress that insect populations inflict on plants and the efficacy of management tactics. For above-ground insects, the mechanisms of behavioral response to environmental factors are often observable, if not always apparent to the researcher. However, this is not typically the situation with soil insects. As a result, field studies of soil insects often quantify only the consequences of behavior while the behaviors themselves remain hidden within the soil matrix (14, 103, 105). Soil ecology research has been productive at the ecosystem level on such topics as nutrient cycling (18), arthropod regulation of micro- and meso-fauna in below-ground detrital food webs (75), impact of microfauna on soil genesis and structure (87), rhizosphere dynamics (17), and energy dynamics of soil systems (79). These examples highlight the importance of multidisciplinary approaches to research programs that unite expertise in insect ecology, soil physics, chemistry, and microbiology as well as systems analysis and modeling (87). Considerable interest also exists in the relationships within soil communities, but these studies have focused primarily upon nonagricultural systems (71, 108) and on the more abundant microarthropod members of the soil fauna ( 106-109). Ecological, morphological, and physiological adaptations of nonagricultural soil arthropods have been discussed in the literature (8, 10, 26, 59); however, insects that are agricultural pests primarily in their immature soil-inhabiting stages have often been studied in detail only in their more accessible adult stage. Although the mobile adult stages of soil pests often determine initial habitat and host selection, a considerable proportion of subsequent host and habitat selection is performed by immatures in the soil, if host or habitat quality deteriorates over time. A major obstacle to the study of soil insect ecology has been the inability to follow soil insect movement and feeding behavior in situ (3, 14, 33, 34, 103, 105). It is critically important in these studies to minimize the disturbance of the soil system through experimental manipulations. R. L. Rabb (cited in 103) notes that the greatest problem with studies of soil insects is that the system is altered through its study. Also, research workers often fail to consider dominant mass and energy transport mechanisms in soil ecosystems. Differences in above- and below-ground environments may alter soil insect sensitivity (over ecological and evolutionary time) to shifting environmental conditions, the movement of chemical cues from potential food sources to soil herbivores, and the mechanisms for soil insect host-finding behavior when compared to terrestrial organisms. In this review we briefly outline several basic principles of soil physics as they relate to soil insect movement and host-finding behavior, to provide a general understanding of the environment in which soil macroarthropods exist. We then selectively review the entomological literature in light of these principles to stress the need to evaluate soil insect behavior within the soil matrix when trying to understand the underlying mechanisms that produce observable behavior. Finally we briefly discuss the importance of behavior in the management of soil insects

Use of Radiography in Behavioral Studies of Turfgrass-Infesting Scarab Grub Species (Coleoptera: Scarabaeidae)

The behavior of turfgrass-infesting scarab grubs in response to soil physical properties may affect the stress that each species exerts on turfgrass and the efficacy of control tactics. To gain a more realistic picture of the events that occur within the soil matrix, we have developed a nondestructive X-ray technique to study soil insect movement and behavior in simulated and natural soil blocks in the laboratory Laboratory studies using this technique were done to determine the effect of some soil physical factors on scarab grub movement patterns. Species-specific differences were demonstrated in the responses of four scarab grub species (Japanese beetle, Popillia japonica Newman; European chafer, Rhizotrogus mqalis (Razoumowsky); oriental beetle, Anomala orientalis Waterhouse; and northern masked chafer Cyclocephala borealis (Arrow) ) to changing temperature and moisture conditions. Studies also were done to determine the effect of soil moisture on the movement and persistence of an insecticide (isofenphos) applied to turfgrass and its effect on European chafer grub movement and mortality This study showed that isofenphos was relatively nonmobile under our experimental conditions, and that insecticide efficacy depended on factors, such as soil moisture, that influence the position of grubs in the soil profile. We believe that a better understanding of the interactions among grub behavior, insecticide persistence, and movement, as illustrated by this research, will improve our ability to manage scarab grubs in turfgrass and will be applicable to additional soil systems